You remember the eFuse controversy? It was a bad time for Android. Android was hailed from the start as an open system, promoting development and tweaking (or hacking). When the Droid X came out, everyone was worried that Motorola was destroying that, and in sense they were.
Despite Motorola's best efforts, the Droid X was rooted recently. It was still unclear whether hacking would have to stop there, or whether custom ROMs would be possible by installing a custom recovery.
Turns out, a recovery hack has been done by Koush, a big contributor to CyanogenMod. This is not a true recovery, but rather a hijack of the normal booting process. It is a really interesting and innovative hack, but it comes with a number of caveats. Check out all the info at Koush's site.