There's actually a long list, but do some looking and you will find plenty.
I bought an EGW knob (it's similar to the Badger style, but half the cost, then had a machinist turn down my handle and thread it.
As far as company's that do them I like SAC, I like the way he blends the handle into the knob.
Just do a search for Tactical bolt handles and you will find (probably an overwhelming amount) a ton of them.
Curt
http://www.snipershide.com/forum/ubb...Number=1670738