"Install Unity" Logos Available?

I'm designing a custom screen for users who don't yet have the Unity player.

Is there an official depository for "Unity" logos, along with any documentation covering usage?

I haven't seen anything like a collection of officially distributed buttons or icons for the webplayer download link. The only graphic I'm aware of is this one:

Install Unity Web Player Button

From the main installation page, here:

http://unity3d.com/webplayer/

However there's no mention of usage terms, and no other sized images in sight. A quick google image search seems to back this up - there are almost no other graphics out there for this purpose which match the terms matching "get unity" "download unity" or "install unity". (contrast this with flash or shockwave!)

I wonder whether - if no selection of icons and buttons exists for this purpose - perhaps it would be worth filing 'feature request' for this at feedback.unity3d.com