Open the Bundle Editor and look at the bottom of the bundle list, there's a button that says "Filter List ..."
You may have somehow turned it off. The TextMate bundle should be in there. Hopefully the checkbox is off so you can turn it back on :-)
It doesn't show in the 'Filter List'. It's not there at all. As I said, I've used GetBundle (which reported success) and tried installing into /Library... via SVN, but it just isn't appearing.
Bruno