While not for sale, I have a 2001 Toyota Prado RV model which has less carpet in than the standard vehicles. Also has manual wind-up windows. The "RV" is the poverty pack of the Prado range. Mine is from the 90 series range which ended 2002. I don't know what the new models are like but the Prado was a very popular 'school bus' driven by parents and many did not go off road. Being extremely reliable and tough, 2nd hand ones can offer great value. If you Google 'Toyota Prado 90 series' you will see plenty of them are still around. The up-market ones had the two-tone paint job, RV just is overall one colour, mine is white.
I also bought a set of rubber inserts, not the little mats but full inserts for front, back seat and rear section. These have ridges around them so you need about 20+ mm of water or mud in the front ones before they overflow, it's like a tub. These inserts/tubs are easy enough to take out and hose down.
Perhaps you could check out the type of mat thing I got and see if they might help with your situation:
http://www.nobullaccessories.com.au/sandgrabberAlso, there are canvas seat covers which actually protect the seat underneath, they are not just for comfort or looks. Something like that would help keep the sand out and you wouldn't have to hose down the inside. : )
So, my thinking is that pehaps with canvas seatcovers or similar and something like the sandgrabbas then you might have more options on vehicles as almost none can be hosed out without damage. At least with a basic vehicle (with minimal carpet) plus the protection, you can have something which is almost as easy to clean as simply hosing it out.