Flashing Android Source - Droid X
eldarerathis is right, you'd need to build the Droid X source in order for it to just work without modification.  Drivers are the main issue here; unlike Windows, for example, Android does not include a vast number of drivers to enable it to work on most any hardware.  Android also runs on much less standardized hardware than PCs.

Most ROMs you see tend to be modifications of the stock image, possibly with custom kernels built from stock.  It's rare that they're fully built from the manufacturer's source, and even rarer when they're built from the AOSP (apart from the Nexus devices).