Guess you were in the right place at the right time. I've also seen a RLBL sport coat for under $500 in 36R with peak lapels years ago, bought it when i stumbled upon it. However since then, never seen a sc or suit in 36R, let alone in my range.
If you do see just let me know! A navy rlbl in 36R for sub $800 would be great!
Do you have an SA at your local mansion?
I have a guy here in Boston who ships in whatever I ask for prior to a sale. Just got an Anthony 42R linen on sale, shipped in from NYC (out of the 10 available in the company). Make friends with an SA and have him check the company for items you are looking for in your size, they will bring them in if you actually buy stuff (which it sounds like you do).