I just recently finished replacing my original torn up Hijet seats. It turns out that the rear passenger seats of a 2002 Ford Explorer have almost the exact same dimensions and can be minimally adapted to fit into the Hijet S110P cab. They're essentially just a brick of foam padding surrounded by a cover that is velcroed to itself, and you take it off of the Explorer seat frame and put it over the Hijet seat frame. Both rear seats only cost $30 total. That's a hell of a deal compared to $90 used for a single seat from a Japanese parts site, and that's not even including shipping fees. My original ripped, stained, moldy padding, rusty-framed seats: Here's how it looked in the 02 Ford Explorer at the junkyard in North Spokane (below): Note that some Ford Explorer models have a combined rear seat bench and no separate middle seat. I was only able to find one in the whole yard that had suitable seats, but there are a ton of Ford Explorers coming and going at junkyards so it's not hard to find one eventually. I had to remove my old seats and strip the foam and fabric off of the frames. I also had to use bolt cutters and a butane torch just to get the old head rests out of the cab, which was annoying. Bolts were super rusted on. The hijet seat frames were also rusty, so I used a rust removing solvent and spray painted them glossy black. Then I trimmed the bottom lip of foam off of the new seats with a bread knife to make them shorter to match the old seat height: I had to remove the entire plastic piece built into the upper half of the Ford seat so that it would sit flat and not feel like I was arching too far forward at a weird angle. The metal frame inside the upper part of the Ford seat can stay because the head rests attach to jt. Then I literally just shoved the upper half seat onto the hijet seat frame, making sure that the padding sits in front of the Hijet seat frame and the Ford seat frame wedges behind the Hijet seat frame in a V shape. For the bottom half of the seat, it just velcroes onto the frame from the hijet (it has no built in frame). Finished product installed in the hijet is in the photos below. You can also fold the seats up to access the engine just fine. Hope someone else tries this out and maybe finds other seat models that might fit.
That really turned out well, great find and thanks for sharing! I have a '93 Sambar that is in desparate need of driver's seat rework, it is trashed and I'm give your solution a try.
@MrJPolito - Thank you for inspiring me to look into after market seats to replace my current (ripped) seats. I ended up snagging two bus seats for $20 and installing them in my 1991 Suzuki Carry. Had to bend the seats forward so they would fit flush. Allowed me to bolt the seats directly into the factory pan by drilling a few holes. Ride height is slightly higher but the comfort and look make a huge improvement (plus you get an arm rest). Much cheaper than the $250 quoted for upholstery.