I completely agree ac-tunnel (or mz) is a useful facility to add to arc, especially to use for once-off hacks, or to figure something out before committing to an xdef. I wrote rainbow just so I could use java libs while playing in arc (among other reasons).
As the author, you get to name your babies. I didn't agonise over java-new, java-implement, or (ugh) java-static-invoke - they're mostly buried under arc macros in any case.
In the worst case, if there's a conflict with mz (or ac-tunnel), I would recommend an excellent symbol renaming hack available on github at http://catdancer.github.com/load-rename.html
