It really goes back to your position and what size bike you would ride on the road. I think I would still want a fairly high bottom bracket because you never know when you are going to be forced into a bad line. I am pretty sure that a good, powerful position would look funny on the sloped geometry, if it's even possible. I understand if you like the look of the sloped geometry, but what's the use if you are dropped because your position is not good? I guess your bike will look good until the organizers pull you from the race. I can assure you from personal experience that is no fun.