Why? When you've got more INB frames than you do sense, the minds plays tricks on you and the experiments get more bizarre as you go.... Worksman offers that Grimeca-style front drum; the rear drum they had, last I checked, was a Sturmey-Archer unit. I already have a Worksman INB with 70mm Sturmey drums, front and rear. I'm not a huge fan of the Grimeca-type Worksman drum, b/c that thing is even heavier than the Stumey-Archer drum.... and every drum brake I've ever seen handily outweighed an XT v-brake.

Further, none of'm outperform an XT v-brake, either. On trails, heat becomes an issue for drums... ask me how I know. =P

I'm building a tenspeed Worksman for trail riding, and the only OE stuff will be the frame itself and the headset cups, which I'm using in my 1.125" threadless conversion. Running a Surly fork. It'll be an exercise in kludge mayhem, and I have fun doing that sort of thing. Don't even ask about my fixed gear/ disc brake INB, which will be done by August. I'll post pictures....

So, yeah, no good reason. I just look at these builds as a mind-teaser/puzzle kind of exercise, then I have fun riding them.