self inflating mattress with non-standard dimensions

Hello all,

I've bought a DMH Oberon tent with inner dimensions of (head, body, legs) 90x132x60 and now I'm trying to find a self-inflating mattress that will be no less than 80cm in the widest part and preferably be the same shape (umm, like a coffin?) as the tent. I've found a couple, but they are all smaller (and I need it to sleep 2 people).

I'd appreciate any ideas or suggestions on where to look or if you know of a mattress that I'm looking for.

Thanks in advance,