Hi Tony,
If you use BPF in place of LPF, the component count doubles for the same order number (5 in the case of QMX) and you'll have to insert series caps into existing inductors, and then parallel inductors to the existing shunt caps. I think you would have to annex the filter if you really wanted to do that, and you'll have to make one BPF per band rather than a group of bands. The only advantage I can think of is that the receiver preselector will be entirely absorbed into the TX BPF. That's an interesting concept but I don't see a way to fit many bands into the tiny case.
Ryuji Suzuki AB1WX