I noticed today that MiniMania now sells a VERY SIMILAR cover:
PET CARGO MAT W/ SEAT BACK & BUMPER FLAP - MINI CO - MiniMania.com
That said, it is similar in design to the OEM version but appears to be padded for "comfort". It also sells for $330, which is the same price they were selling the OEM version for (the OEM version from MINI is priced at $280).
It seems to me that these are very easy to make and are hardly worth $330. I REALLY WISH I could get an OEM one as they seem to be better at protection (particularly water).
Could someone that actually has an OEM version in their hands measure it & take pictures? Id imagine that it's simply a square floor (not contoured) floor piece with 3 sides and a large flap to stick out the boot.