Hey John, I've got a low elevation yew stave thats 62" long and maybe 1 3/8 or even 1 1/4 wide about 8 inches off the fade. Bow is too short for a ELB I think. My plan is to attempt a semi bending handle, slightly rounded belly, add minimal recurve (enough to improve string angle but not lose too much working limb) and get as much limb bending as I possible can. The tiller will be a "fat" elipse, not a circle, but closer to that than a classic elliptical tiller. Just sounds like a similar situation to what you're facing (except of course, mines a stave not billets).
Good Luck, looking forward to seeing how it turns out. Maybe I'll post some pics of mine soon also...
Gabe