yeah its a revelation, no matter how good you thought it would be or how good your previous gear, the Matamp in the band always sounds better
I'd avoid the 2x10 since it woiuldn't split the power equally between the cabs, probably cheaper to get another 6x10 anyway
I did always toy with the idea of sticking a 6x10 ontop of my 4x10 but it seemed excessive so I'm going to get the 1x18 instead .
I should really get a flightcase for mine, how much was yours (if you don't mind me asking)? I keep mine in an plastic army box (one of the ones they drop from planes) and the hinges have made 2 nice holes in the tolex on the side, down to the wood, bit of a pain but hey we buy them to use and abuse them.
I should really get the cover for my 2x12 as well.