Is anyone out there Biamping their Proacs?

Regarding the Proac match with tube amps, that's not necessarily true.
Stuart Tyler, the owner of Proac, uses Sugden Masterclass series to listen to his speakers at the Proac Factory. I'd buy a pre-owned Sugden Masterclass int-amp( around $3,5k) and be done with it.
Sugden is one of the few brands you never hear about, because they refuse to spend dough on kitschy advertizing.