If you can source some used seatbelts from an area of the country that doesn't get hammered with UV like we do here in the Southwest, they should be in decent condition and safe to use.

Finding something aftermarket that will fit and work like stock is going to be difficult - plenty of race harnesses out there and even some generic-fit retractable units, but none will fit/work like stock.

95 Montero SR
3.8 MIVEC, Advance headers, 2 1/2" exhaust, Magnaflow muffler, OME shocks & rear springs, 2" body lift, 3" tank lift, 4.90s, TRE front locker, factory rear locker, Roger Brown Rock Sliderz, 315/75r16 (35") tires, Sport big brakes