Easy to do. I'm making three of them, two for sale and one for personal use. Pictured are enough parts for the two I'm selling (The one I'm keeping won't have a flashlight mounted in it). Each grip needs five things:
Aimpoint 30mm rings w/ spacers (eBay has plenty of these)
Flashlight (I prefer a Surefire 6P or Classic) with tape switch
PEQ tape switch
Two button pressure switches (I prefer click types)
If you're into the gangster grips, none of that list should surprise you. Aimpoint rings are the best I've found to make gangster grips with. I'm working on this project over a few days (waiting on some hardware to come in from Brownell's), and as I build these I'll update the thread.