zompist bboard

Does it occur in native vocabulary in any environments that aren't word- or root-initial? I seem to recall PIE *bh *dh became in most non-initial positions.

Any example I can think of off the top of my head is either word-initial, of foreign origin (Africus), derived (efficiens < ex facio), or a compound (-folius, -formis, etc.). Isn't this expected, though? I was under the impression that Latin was distinct from other Italic languages that have the unconditioned change of Ch > f.

Zaarin is right. Words that have /f/ in non-root-initial position, like rufus, are normally regarded as loans (in this case, from Sabellic).