Nope, Massassi didn't have it. They're great, but they don't have everything.
I think the reason it never appeared on Massassi is that files submitted to Massassi require a "readme" documentation. This map was stupidly created without any kind of info. So if somebody wrote up a reasonable looking readme file with the author info and the disclaimer that it's not made or supported by LucasArts, that it's for JK (and not MotS), etc I'm sure it could be added through the normal channels.
Speaking of obscure levels, anybody know about a MotS map called "De High Dive" ("The High Dive"?) Basically it was just a big room with a GIANT platform that you went up on an elevator I think and then leapt off and fell into some water. It was just a kind of cool idea. But no readme included. I got it off some stupid "hax" site, but the map worked fine. If anybody has that, let me know...
We really should get a page together with all the old JK1 maps that people are looking for. If we can't submit them to LucasFiles, we should at least get together a "classic JK1 files" page for JK.net.
[arg, forum troubles, sorry for multi-posts...]