@Knebel
I remember some time ago you made a comment about a traumatic back injury and I wondered how you've been doing with it.
My idea on seats:
I've had 2 Lincoln Mark VII LSCs in the past and the front seats are VERY supportive. In fact, the way the front doorpanel molds in toward the driver, I actually felt a little cramped the first time I got in one. But I quickly learned to like it, and it really is a good driving enthusiast's car.
Unfortunately, getting 2 seats in usable condition will be a bit tough nowadays, recovering will be required. It was actually tough years ago, as the side bolsters wear just from getting in/out of the car.
You MUST get the seats from around 87-89, as the later '90-92 seats look similar but are NOT the same and won't hold you as well. Due to the heavy wear happening on the bolsters they redesigned the seats (I read that somewhere) but more likely the wear wasn't that fast, but likely there were complaints about them getting in the way for ingress/egress for the old dudes.. (my hunch)
Top 2 pics are the seats to look for, the steering wheel is a good 1st clue, although donor-car seats might not be original at this point.
So - look for the separate segment at the knees as a sure-fire clue (it is power adjustable, FWIW).
The 2nd pic compares to the later seats. The green circle bolster is noticeably bigger when comparing them. I don't know if the knee/thigh bolsters were 'diluted' also. Note the different steering wheel used on the later cars, and the obviously-non-adjustable knee bolster.
These seats have a lot of adjustment to them, the movement controls are in the doors, and the lumbar, etc, switches are on the seat itself.
Note the adjustment of the knee section in the tan seats.
The burgundy seats have perforated-leather inserts, but I have seen these seats in teh same color and velour inserts, in a slightly-brighter color. I don't know how well those colors would work for you, or if you'd even find a usable pair of seats in that combination.
Aside from that, I'd go prowling a JY and see what modern seats feel good to you and are usable as-is.
Be aware, though, that any modern car with a power seat with memory settings might be a hassle to retrofit as the memory might be wired into a body module. I found this out with these late-model Chrysler 300 buckets I got for my 300L. (bottom pic)
Modern seats will have a bunch of wires (mine have 2 connectors of 20+ wires each, circled) although most of the wires are NOT needed (airbags, occupant sensors, seatbelt buckeled, etc).
One benefit of modern seats is the catalysts are at the engine, and the floorboard can be relatively flat.
These 300 seats look like the mounting bolts are in a nice squarish pattern, and all on the same plane.
I don't know how supportive they'd be for you, though. there are probably better options (Camaro, Mustang, Lincoln, Cadillac, etc)