Flashing Android Source - Droid X (I previously asked this on StackOverflow and was directed here.)

I'm hoping for some clarification on the requirements and/or process of flashing a custom build of Android to a device. I've built a stock version from the AOSP and tried a few different times to flash it on my Droid X, all unsuccessful. I was thinking (or hoping) that the process of rooting the device would also unlock it to allow this, but maybe that's not the case. It looks like the phone still can't be touched at kernel level.

Anyone know what's up here? There's a lot of ROMs for the DX, so it seems like there's a way, or do all those ROMs modify only a superficial level of the Verizon image? I just want to know what's going on under the covers.
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).