Guys, this has NOTHING to do with "engineering constraints". Threre are 3 simple reasons the Pre lacks a microSD slot:
1. Greed (they want to sell all of us the otherwise identical 16GB Pre at full reail price that'll arrive 6 months after the 8GB version
2. Money (Palm's notorious known to be notoriously cheap and skimping on critical features
3. Desperation. Palm's trying to mimic Apple in as many ways as possible (you can thank Ruby for this) while one-upping them in a few others (slide-out keyboard, removable battery, Synergy)
Apple can get around charging more $ for fewer features due to the perceived aura of exclusivity and quality surrounding all things Apple brand. Let's face it, Apple carrier a certain cachet that few other electronic/computer companies have.
Just look at Apple's entire lineup: none of their devices, iPods, laptops, or desktops, have standard card reader slots, for example--yet the cheapest $250 generic Linux or Windows netbook has at least an SDHC slot--go figure!
The Pre's a compelling device from a formfactor standpoint, sure. But Palm's made a few horrible design decisions that will easily take it out of contention for power users. The pitiful battery capacity is one, the lack of a microSD slot are the biggies IMO. The lesser points that can be debated--no backwards compatibility, no IR port, no stylus, no desktop Hostync--are more of a matter of user preference but I still think Palm's being a bit too arrogant in completely turning their back on 13 years of legacy Palm OS users & data. Old habits die hard and some people are completely fine with Hostyncing and taking baby steps into the cloud, dangit!
Palm & Sprint are both pretty low on the perception ladder nowadays, so those 2 fading companies pinning their hopes to each other makes sense in an ironic way. I have a feeling that Palm's utter devotion to Sprint is going to cost them in the long run.
I'd rather have 512mb onboard + a microSDHC slot than a fixed 8gb internally.