Was wondering…
Regarding Feature #8 listed here: http://unity3d.com/whatsnew-1.6.html
Does this mean that a player can spraypaint onto a surface in realtime during a game?
And if so, can that sprayed surface be saved?
Yes ( http://forum.unity3d.com/viewtopic.php?t=2668 ). To save the data you’ll have to use any of the interfaces available to send the data out (System.IO.File, WWW, Sockets, …).
d.
edit: David is the fastest… 
Also have a look at the game A Tack! by Matt Diamond.
“3DU” Game Competition Results → 2nd Place to download it.