I've seen metal flutes with wooden headjoints but has any one seen or played metal or plastic piccs w/ wooden headjoints?

No, I haven't ever seen it but it could be done.
One possible problem would be with the piccolo's bore. Many metal piccolos (though not Gemeinhardt or Haynes) have a cylindrical bore, like a flute. The headjoint for such a piccolo must taper toward the crown.
All of the wood piccolos that I know of (although I'm sure there is an exception somewhere)as well as the resin/plastic ones have a conical bore. (The body of the piccolo tapers toward the 'foot' end of the piccolo.) In this case, the headjoint is cylindrical.
If you were to put a wood headjoint on a cylindrical metal piccolo, or a metal tapered headjoint on a conical wood piccolo, the instrument would have 'fatal intonation errors'.
This is mostly theoretical, since the tenons for wood and metal piccolos are usually not the same and would not be able to be fitted to one another.
You could theoretically put a wood headjoint on a resin-body piccolo, but I have not seen this done. I have seen custom piccolo headjoints put on the less expensive wood piccolos, such as an Eldred Spell headjoint on a Yamaha 62 piccolo. The newer model resin piccolos might change this, though, since Sonare and Pearl have both come out with excellent inexpensive (but not cheap) resin piccolos that have had good reviews. (I have only tried the Sonare, and briefly.)

Thanks!

I've played a metal body with a wooden head, and a seen a plastic body/wooden head combo. They exist but are somwhat less common than other styles of picc.