Might be ugly?
I have read several references at SMC on the desirability of solid wheels. Of course, it adds weight and cost to a saw. I am not a saw designer by any means, but for my money, I think if you're adding weight, I'd want it in the frame first (all design is a compromise).
A BS is tensioned by 2 springs, one inside the other - so to speak: the 'official' tension coil spring, and the 'spring' (action) of the frame. The relative forces that each will support have to be balanced, but no matter what the coil spring is doing, ultimately the frame has to support the tension load of the blade.
...where did I leave that welder?!?