I just went to
www.quaifeamerica.com and I now see the offer two differant gearboxes for v8 v10 &v12 RWD applacations. The are also the mechanical style, Like we used in the Hondas.
Scott, here is a like that will tell you how the guts of one works, Its not 100% correct, but you will get the idea.
http://auto.howstuffworks.com/sequential-gearbox.htm
It still looks like its gonna set you back about 18K-20K by the time your done.
Also, Take a look at there differentials, they are also pretty sweet. I will take some pics of the one I have for a ford 9". I have had this thing for about 7 or 8 years sitting on the self in the garage, ordered for a customer and they never came and pick it up, lucky I did get a deposit.