screen to world coordinates issue

Scripting
1 
using UnityEngine;
using System.Collections;

public class zumSelectObjects : MonoBehaviour
{
    Vector3 mouseStartPos, mouseEndPos;
    bool hasStarted, hasEnded;
    Vector3 selectPointStart;
    Vector3 selectPointEnd;
    public Transform target;

    void Start() {}
    void Update()
    {
        if (Time.realtimeSinceStartup > 5.0f)
        {
            if (Input.GetMouseButtonDown(0))
            {
                mouseStartPos = Input.mousePosition;
                Debug.Log("Start X" + mouseStartPos.x +" : Start Y" + mouseStartPos.y);
                hasStarted = true;
            }
            if (Input.GetMouseButtonUp(0))
            {
                mouseEndPos = Input.mousePosition;
                Debug.Log("End X" + mouseEndPos.x+ " : End Y" + mouseEndPos.y);
                hasStarted = false;
                hasEnded = true;
            }
            if (!hasStarted  hasEnded)
            {
                selectPointStart = camera.ScreenToWorldPoint(new Vector3(mouseStartPos.x, mouseStartPos.y,1.0f));
                selectPointEnd = camera.ScreenToWorldPoint(new Vector3(mouseEndPos.x, mouseEndPos.y,1.0f));
            }
        }
    }
}

Ok, so what I have at the moment, is 2 vector 3’s one with the starting point where I clicked on the mouse down, one is the ending point where I let go of the mouse and adding a depth of 1.0f distance (1 meter), I have been trying to figure out how to then take all of that information and draw a cube starting at the start position and ending at the end position, but the only thing I can find in the docs is a cube from center point and size, ok, well I can deduce all that really from the math of the 2 vector points and have the orientation the same as the camera, but I can’t get the box to actually be created, I have written this thing over and over many times, I even tried to do a GUI based on the x and y but that gets all goofy and doesn’t start the GUI in the upper left and stretch to lower right.

This is driving me nuts, I figured this was going to be easy
Edit:
To further confuse myself, I added a gizmo to see where on earth it was thinking the point is, so add this to the code above (FYI I attached that code to the main camera)

    void OnDrawGizmos()
    {
        if (!hasStarted  hasEnded)
        {
            Vector3 p = camera.ScreenToWorldPoint(new Vector3(selectPointStart.x, selectPointStart.y,camera.nearClipPlane+20.0f));
            Gizmos.color = Color.yellow;
            Gizmos.DrawSphere(p, 10.1f);
        }
    }

No matter what the x,y,z of the start point is, the gizmo always draws the sphere in the lower left at 0,0,0 with a radius of 10.1f, so it isn’t retrieving the value of the selectPointStart for some reason, but it has a value.

2 
using UnityEngine;
using System.Collections;

public class zumSelectObjects : MonoBehaviour
{
    Vector3 mouseStartPos, mouseEndPos;
    bool hasStarted, hasEnded;
    Vector3 selectPointStart;
    Vector3 selectPointEnd;
    public Transform target;
    bool pointSet;

    void Start() 
    {
        pointSet = false;
        hasStarted = false;
        hasEnded = false;
    }
    void Update()
    {
        if (Time.realtimeSinceStartup > 5.0f)
        {
            if (Input.GetMouseButtonDown(0))
            {
                mouseStartPos = Input.mousePosition;
                Debug.Log("Start X" + mouseStartPos.x +" : Start Y" + mouseStartPos.y);
                hasStarted = true;
                hasEnded = false;
                pointSet = false;
            }
            if (Input.GetMouseButtonUp(0))
            {
                mouseEndPos = Input.mousePosition;
                Debug.Log("End X" + mouseEndPos.x+ " : End Y" + mouseEndPos.y);
                hasStarted = false;
                hasEnded = true;
            }
            if (!hasStarted  hasEnded)
            {
                if (!pointSet)
                {
                    selectPointStart = camera.ScreenToWorldPoint(new Vector3(mouseStartPos.x, mouseStartPos.y));
                    selectPointEnd = camera.ScreenToWorldPoint(new Vector3(mouseEndPos.x, mouseEndPos.y));
                    Debug.Log(selectPointStart.x + ":" + selectPointStart.y);
                    pointSet = true;
                }
            }
        }
    }

    void OnDrawGizmos()
    {
        if (!hasStarted  hasEnded)
        {
            Vector3 p = camera.ScreenToWorldPoint(new Vector3(selectPointStart.x, selectPointStart.y,camera.nearClipPlane+20.0f));
            Gizmos.color = Color.yellow;
            Gizmos.DrawSphere(p, 10.1f);
        }
    }
}

Now to my knowledge, that script should have created a sphere gizmo that stayed at the location specified, but it still sits at 0,0,10.1f of the camera. This next block at least appears to drop the gizmo sphere at some point, just not where I would think it would be dropped, can’t really tell where it put it.

using UnityEngine;
using System.Collections;

public class zumSelectObjects : MonoBehaviour
{
    Vector3 mouseStartPos, mouseEndPos;
    bool hasStarted, hasEnded;
    Vector3 selectPointStart;
    Vector3 selectPointEnd;
    public Transform target;
    bool pointSet;
    Vector3 p;

    void Start() 
    {
        pointSet = false;
        hasStarted = false;
        hasEnded = false;
    }
    void Update()
    {
        if (Time.realtimeSinceStartup > 5.0f)
        {
            if (Input.GetMouseButtonDown(0))
            {
                mouseStartPos = Input.mousePosition;
                Debug.Log("Start X" + mouseStartPos.x +" : Start Y" + mouseStartPos.y);
                hasStarted = true;
                hasEnded = false;
                pointSet = false;
            }
            if (Input.GetMouseButtonUp(0))
            {
                mouseEndPos = Input.mousePosition;
                Debug.Log("End X" + mouseEndPos.x+ " : End Y" + mouseEndPos.y);
                hasStarted = false;
                hasEnded = true;
            }
            if (!hasStarted  hasEnded)
            {
                if (!pointSet)
                {
                    selectPointStart = camera.ScreenToWorldPoint(new Vector3(mouseStartPos.x, mouseStartPos.y, camera.nearClipPlane + 20.0f));
                    selectPointEnd = camera.ScreenToWorldPoint(new Vector3(mouseEndPos.x, mouseEndPos.y, camera.nearClipPlane + 20.0f));
                    Debug.Log(selectPointStart.x + ":" + selectPointStart.y);
                    p = camera.ScreenToWorldPoint(new Vector3(selectPointStart.x, selectPointStart.y, selectPointStart.z));
                    pointSet = true;
                }
            }
        }
    }

    void OnDrawGizmos()
    {
        if (!hasStarted  hasEnded)
        {
            Gizmos.color = Color.yellow;
            Gizmos.DrawSphere(p, 1.0f);
        }
    }
}