Tricky, Apparently the "TweakUI" program can hide it but I don't know if it works for 7, otherwise try these ideas but they are for xp so may not work. :
Hide Recycle Bin using Folder Options
Customizing Your PC with the Windows XP Registry
How do I make the Recycle Bin appear on my desktop in Windows Vista or in Windows XP? (for restore info after using TweakUI program)