According to Eric O'Brien:
What are folks doing that makes them want to see built-in ftp/sftp/ ssh support in TextMate? One situation I can imagine is the desire/
I don't really care about it, I either use a distributed VCS such as Mercurial[1] to have copies *with history* for files I do really care about or I use Fugu/Cyberduck-kind of program.
----- [1] http://selenic.com/mercurial/