I've been intrigued by this.
I'm looking into getting mp15-22.com's barrel nut conversion to run standard ar-15 handguards. Then add the magpul carbine length handguard to it accompanied by the standard a2 front sight post.
Two options I have found:
Paintball Barrel M4 Front Sight Post
its made for paintbal guns, but mp 15-22's don't need this to function as anything more then a sight...
Also found this:
A2 front sight clamp on w/screws
What do you guys think?
edit:
also, whats the piece called that I pointed out in this picture:
http://i6.photobucket.com/albums/y212/DMN0166/mapul1.jpg
I noticed that doesn't come with either mp15-22's kit or the magpul handguard.
thanks.