i got a full leather rear setup from a donor car on kijiji (like CL up here). it really IS a lot better - it's just the same softness as the ZHP rear leather seat.
my 9-year old son complained that the leatherette was really uncomfortable on his FIRST ride in the car - yep, he's definitely my son.
he said "the ZHP back seat is so much more comfortable!" not that i would doubt him, but i was curious so i climbed back there and yep, it was a lot harder than the leather in the ZHP - especially at the lowest part of the seatback, where it hits your butt/lower back - it's like a rock right there. and the leatherette just feels cheap, and plasticky (cause it is). so i had to find a leather rear setup.
so...
OPTION 1
check the scrap yards, CL for a Touring partout, etc... it's worth the expense and effort.
OPTION 2
find some M3 rear seats and use the nappa leather to make a matching rear set (the montana leather grain doesn't really match the nappa well at all... but i don't mind. it's definitely a better match than the leatherette!). i actually have two full sets of M3 rear seats because i was going to harvest the leather to recover the leatherette rear seat, but i found the montana one already done, so hey, that's a lot less work.
but if you have a good upholsterer, it should totally be possible - the dimensions are very close and should not need a lot of alterations. i would be willing to part with one set if you're interested, for not much money.