I'm interested in this too.
I'd like OEM carpet mats, but the front cab mats are two separate mats which don't cover the whole of the cab floor and mat for the middle doesn't go under the seats.
I've had Leighton Vans mats. but the heel pad was in the wrong place and the middle mat didn't extend under the seat.
I now have Harrison's trim supplies mats - they are nice quality and the fit is OK, but after 12 months I haven't been able to get the corners to lay flat yet.
I'm going to consider looking for somebody to do a custom set soon.