A further follow-up:
Manually purging ~/Library/Application Support/TextMate/Cache and relaunching TextMate seems to finally force a module reload. This is necessary for me after *any* bundle installation, before that bundle will appear.
(I had already tried purging several other cache directories, but not this one evidently.)
So:
- To future users whose bundles mysteriously don't seem to load: rm -r ~/Library/Application Support/TextMate/Cache
- To the developers: any idea why this is happening? Is there any more information I could provide to help track this down?