I've been searching high and low, and have only found a small handfull of US Marine figures out there. I've seen a few on Verlinden's site, but nothing else.

I see ETO based figures left and right, and it almost seems like the model/resin makers out there have forgotten about the PTO. Anyone have any good leads on where I can find some more USMC related stuff, or am I about to delve into the world of scratchbuilding?

Here are a few that come to mind:
Masterbox MB3589 and 3544
Dragon 6408,6272, 6379, and 6554

Masterbox and Dragon are styrene multi figure sets in 1/35th scale. Verlinden has numerous figures as does Warriors, all 1/35th resin. You should be able to find some of the Warriors sets online at Squadron.You can also find a nice BAR gunner here http://www.coloradominiatures.com/search.aspx?manufacturer=83

Thanks. Apparently my Google-fu is off, because I couldn't come up with hardly anything!