HUGE thanks to Jumbo240z for helping out (considering he did most of the work), couldn't have done it without you, Jon!
picked up a set of 1st gen. MR2 seats at the junkyard = $52 for the pair. These are light (about same weight as stock Z seats), and the driver's seat has adjustable side bolsters, adjustable thigh support, and adjustable lumbar. The head rest also tilts forward and back in 5 positions. These were initially very dirty, but not a single tear in the fabric!
Jumbo240z in action, removing stock toyota mounting tabs. These were hardened steel that was welded AND riveted. What a bitch! After that we took a trip to the hardware store and picked up some angled mild steel (2x3foot bars), 8 grade 8 3/8s x 1" bolts, nuts and lockwashers. $17 total. also $14 worth of sawzall blades.
Measured up the placement of brackets (these would put the seats just a hair lower than stock placement, but provide much more rigid support)
Finished passenger side product. Welded up brackets with holes drilled. We had to drill out new holes in the rear brackets, and the front bar went over the stock location. We did however relocate the mount point closest to the rocker panel because the bolt would get caught on the latch cable.
Installed product: these definitely pass the butt test, and are a HECK of a lot comfier than stock datsun seats. Bolsters grip you in very well, and thigh support kicks ass. Granted, these are no recaro/corbeau seats, but for a total cost of under 90 bucks definitely makes this a worthy upgrade!