Best price I've found is plumbersurplus.com direct with free shipping (you find them also on ebay and amazon). I'm still trying to find a better alternative, but it seems the ones that end up on ebay have been surplus aquisitions from Intel or aerospace or some application that would make it questionable for potable usage.
(Although, I did ask Little Giant what kinds of chemicals would render the pump unpotable and he said he couldn't think of any...). There is a 3-MD-HC on ebay right now for $71 that was from Intel. Been there a little while. Seems as though the folks who buy this for brewing don't get rid of them (as opposed to March pumps).
and don't forget the 2-MD-HC. It's really not that different than the 1/25 hp 3-MD-HC in terms of power. It's the one I'll be getting.
EDIT: D'oh! Sorry, should have read more of the post.