You sure you want a 'primitive' bow? (no glass?)
there's this too... qualifies as primitive.. simple to make... good for 3 fingers imo. effective.
https://www.youtube.com/watch?v=G04l68aeSz0
For a custom 100lbs hornbow, I would expect to pay $2000-3000 for one, but I'm not sure. 1 year is enough, sometimes even 8 months. Or maybe they'll have a heavy one in stock.
Jason Beever, Alex Wittenaar and Jj Weißnicht are good bowyers.