So I got back to this again today. 

Try also: PATH=/usr/bin which ruby

]2; /Users/cassio/Desktop ]1; cassio/Desktop /usr/bin/ruby


I've no idea why I got this weird output (it works fine in tcsh and bash outside TM), so I just commented out the line in the ruby bundle that depended on `which`:

# export TM_RUBY=$(which "${TM_RUBY:-ruby}")

and everything works now...

Cassio