1) load the meta deps from a source, define the methods, load the deps, then undefine the methods

2) change the DSL: instead of
tmbundle 'blah'
use
dep 'blah', :extends => :tmbundle

3) another DSL change:
using_meta :tmbundle, 'blah'

4) introduce a convention - dotted extensions mean meta names, e.g.
dep 'blah.tmbundle'