Yep, know exactly what you mean.
I always intended to buy an R80 G/S and an R100GSPD but both now command fairy tale prices.
I was lucky enough to snag the R100RS JPS last year, and I only had to pay slightly over the ce what it cost when new :-). Still it looks lovely parked next to the 1978 R100RS I have owned since new.
There are really only two more Airheads I want badly, firstly a last model R100RS and a Krauser MKM 1000. To my surprise the Krausers are readily available, most of them having led pampered lives since new. I am in negotiations for one at present which has an interesting history, the price being asked is acceptable, just waiting for an inspection report - wouldn't you know it, the guy doing the inspection caught Covid so all on hold till his recovery is complete - the bike is in the UK and he has to travel a county or two to get to it.
Last model R100DSs are thin on the ground, the world had pretty much passed them by when the last ones rolled off the line and sadly most of those that did sell went to RS Travis a d are "well used".
So, I do sympathize in fig do g yourself a decent R100, so many have been butchered by the cafe brigade l, but I suppose that put few very necessary parts into the market.
Good luck.