I did my own CM7 SD card today, and even modified it to make it dual boot. It wasn't difficult, but I totally understand why people buy the ready-made.
Either way, this booting from SD card is awsome! If you don't have a dual boot card, just pop it out and you're back to stock BN OS!
I don't think I would have been comfortable rooting it any other way, but this feels really "safe" (as much as anything involving anything even remotely related to computers is "safe"...).
