Re:
I love my lts, got a brand new RS superdeluxe when icycles had them about 10 years ago. Wasn't the 97 hard anodized finish but a silver 99 sts one. Rebound now clicks but it still does naff all, treacle or pogo! It's only done about 3 hours cycleway riding since so should be good for a while to come.
The full moon cycles travel chip mounted conversion was pretty ugly but looked to do the trick at a reasonable price,website is still up but isn't advertising any in stock, pretty sure if pushed, he'd knock one out. He used to have an eBay advert that advised what frames it would work with and if I remember, it's only lts or sts with the top frame pivot mounted behind the seatpost. As my frame looks like no other I've found and that pivot is in front, it doesn't work for me with the shock top mount fouling the seat post.
The jekyll mod is another option, got to be the first gen jekyll as they went back to eye to eye mounts after. Trunnion needs machined out and re-threaded to suit the Fox shock though.
Otherwise, yeah if the body of any coiler shock is the same diameter or a little bigger thanj the RS, then it should go in providing you can get the trunnion onto the threads. Problems I see with that is getting a shock with that tiny wee 1.75" stroke and anything you get will be just as ooold in the tooth as the RS surely?
Really the best option would be creating your own adapter out of 3 bits of string and some double sided tape or getting one made up to suit. Getting into newer shock technology is the way to go and adapter plates would allow you to get it at the back.