Send Palm's customer service a nasty email. If enough people do it, it might kick someone into gear. I don't know how ANY decent sized hardware company can choose to not support a 64-bit OS, considering every new CPU being sold now is 64 bit and the universal migration to a 64 bit OS is inevitable.
Based on the research I had done, this is one of the oddities insofar as migration, especially from a larger company. It seems the folks who write the software were purchased, acquired, taken over, or whatever vernacular you'd like to use, is a company called Access. It seem they have just about 6 months or so ago developed the Palm OS Sync'ing software for Vista x86
Like you said, weird, and with all of the Palm Treo owners out there, you'd think enough complaints would have already been made. Another commentary I had seen was the one where some software and hardware manufacturers figure if they don't write the drivers, Vista will simply disappear. Now while this sounds absolutely appealing, it ain't gonna happen.