Yes, the T90 will be a much better choice for FTA. T55's have their value, don't get us wrong, but not for FTA and the receivers you have really.
As for your question, like I stated earlier I personally do not know of anything that can do what you want and allow the 3 receivers to have seperate programming/channel/polarity changes.
It's friday and I'm having problems focusing tonight..., but one way I think would be the fewest wires in to the house would involve something like this
Each LNB (dual output LNBs) is fed into 2 4x4 multiswitches
Then each output from the switch would go to a 22khz *edit (also, a simple diseqc could be used instead, actually might be better as I can't remember if the 4x4 uses 22khz to switch internall, if they do, then you can't use 2 22khz in a row, I'm just out of now, it's been too long a week so someone will correct me here if I'm wrong)
Then each 22khz (or probably better each Diseqc) output to 1 receiver
I attached a diagram to visualize it. However this might qualify as one of the worst diagrams ever done on the site, but hey, I did it in paint.
Also, realize that others who understand switches better might have a better solution
*edit:
as soon as I posted it, I realized I think I messed it up.
Insted of the outputs of the LNB's going to 2 different 4x4's, each output would need to go to the same MS. LNB 1-2 would go to 1 switch and LNB 3-4 would go to the 2nd switch, not crisscrossed like I have them in the drawing.
I'll try to upload a revised one.