I suspect your limitations will include individual tire load and speed limits. it would be fiscally untenable for an airline to have to buy a unique tire for a low-production airplane. OTOH, if you can put enough wheels on it...
Also, I think a blended wing-body concept would fare better than a conventional fuselage+wing design for something that large.
All those considerations are beyond the "need" for an airplane larger than the 747 or A380 in the first place...