From reading through, I got the impression you'd already known and been using Heimdall. Grr!
Thanks for all this! This is FANTASTIC! ...but I assume this only works on a particular version of the Galaxy Tab? (i.e. SCH-I800 is the one I have. I didn't see any notes about which versions this should or might work with... or which version you had used to do all this.) Kudos!