The newer ones (i.e. what would likely be on clearance) don't have Flash ROM, appearently. A minor inconvience I suppose, as you could just load Linux from within Palm OS, but you can't flash Linux too it.
I'll keep an eye out for deals on the Zodiac either way, it will probably be a while before you start seeing them clearanced. Hmm... Might be some Ebay dumping of these, as appearently the games are DRM'ed to a specific Zodiac, and you need Tap Wave to re-activate them if you move to a different Zodiac (due to loss, damage, etc.). With them no longer supporting it, users will be paranoid.
Running Linux or Windows CE, which have a decent number of free emulators, this handheld would be pretty cool. Palm OS was lacking in the emulator catagory when it was realeased, and most that came after (intended for the Zodiac) are for-pay.