One of my guildies has apparently felt inspired by my ramblings here and is starting up his own blog! Unlike me however, he's planning to actually provide some useful information, which makes it even better!
"Squishy Shadow Tank" can be found here. While I've established before that I'm not a mathy person and thus not a good judge of the validity of any given theorycrafting, I would like to say that this is the same guildie who has given me pointers for how to gear my Commando and I've already seen the positive results of his advice in action.
He's only got one post up so far, but even that should already be quite useful for any aspiring tanks out there (of any class really). This healer at least definitely agrees that tanks with good mitigation rock our worlds. I've ended up being assigned to healing the same Guardian tank in our guild for several operations in a row now, and that man sure knows how to gear and cycle his cooldowns correctly. The first time I healed him I actually whispered him afterwards to say something along the lines of: "WTF man, you took almost no damage!"
Now you, too, can learn how to be a tank like that (especially if you're a Shadow)! Just go and click on the link already.