([...] I only know the TS-E 24mm 3.5 L II I just sold was a plasticy monstrosity)
The 17mm version is almost all metal, and I have read everywhere that it's essentially identical to the 24mm build-wise. The-Digital-Picture's Bryan Carnathan writes
: "The Canon TS-E 24mm f/3.5 L II Tilt-Shift Lens is, optically and physically, the highest quality 24mm Canon-mount lens I've reviewed to date." As far as I'm concerned, the 17mm is already hefty enough, but I have no qualms about its handling (aside from the unavoidable care required for protecting the front element, which isn't such a problem for the 24mm version). The focus ring is amazing. Even without having used the 24mm, I think I'd have to say either you're crazy or you have the new 24mm version mixed up with something else. It might be your opinion, but as an ambassador for the FD lens line, such a statement yells "my nostalgia glasses tint new things puke-colored!" to me.
With older lenses, particularly TS lenses from the FD era, I have to work from the assumption that they aren't as good optically and even mechanically as newer versions, until proven otherwise (and the amount of research time I put into plunking even $50 down on a lens more or less precludes me from buying because "it's cool because it's old" unless it is $20 or less). Yes, it's a shame that Canon hasn't seen fit to release a newer version, but there's lenses that can be pressed into service for that focal length range (the 17mm works as a 28mm on APS-C, and the 24 should overshoot the mark a little (for just over 38mm), if not on full frame. Without any online tests, there's no argument for me to point to that the lens is good enough - for the money.
Without some kind of test data to point to, trying to sell the lens at either $600 or $1000 is not what I'd call a sure bet. I've been around long enough to know that lots of people put things up for sale at hopeful price points (I've even bought some), eBay or not. I'm happy there's a dedicated group of FD to EOS connoisseurs but when I buy an EF lens I'm also buying into the assurance that it isn't going to be obsoleted by a product announcement. How sure can we be that TS-35mm-to-EOS fans will stick around to buy a copy if a new TS-E 35mm was announced?
You are selling something. I realize it's done as a hobby and that "the CR guy" has given you his blessing, but I hope nobody thinks it unjust for me to say that I think it's excessive to to hype up old lenses without any profiles for digital cameras available online, while calling one of the new TS-E lenses a "monstrosity." Instead of hype, "magic," and possible FUD, I would rather see some MTF testing of old lenses. (For what it's worth, the first definition of the word "monster" is a creature made up of parts from different animals, which isn't a description of a native EF mount lens.)