Currently running my Breton Sorc as a battlemage tank. Not the best tank around, but I've done a fair number of vet dungeons with him so far. It was more to test a theory that to actually produce a tier-1 tank, but I figured I'd share it anyway, especially since he's been fun to play.
5 Thunderbug, 5 Storm Knight, 1 Iceheart.
Frost staff bar: Inner Rage, Dark Deal, Ele Drain, Bound Aegis, Power Surge, Ice Comet.
Lightning staff bar: Blockade, Splash, Shattering Prison, Boundless storm, bound aegis, eye of the storm.
I have all my attribute points into Magic, so I'm usually only around 29k health. Magic is about the same. If I use the resistance mundus, I can get my physical to the cap and then my spell is > 40k, which is overkill. I usually opt for increased crit chance on the mundus, to give me more inbound heals from power surge.
Play style is a lot of positioning to CC as many adds as possible, and keep them in my lightning AOEs to try to proc concussed, off balance, and maybe the implosion disintegrate. Taunt the "flyers" with either the frost heavy (slow) or inner rage (quick, but resources).
He does much better with magicka dps than stamina since I'm not running the 1h/s taunt.
There are a lot of changes I could do to make him a better tank, but honestly, when I'm in the middle of a mob with Boundless Storm, Elemental Blockade, Eye of the Storm, and Lightning Splash all running and that Thunderbug proc goes off, and my health bar isn't moving or is refilling as fast as it drops due to Power Surge, it really is a thing of beauty.
8-hr/day casual on Xbox NA. 20 Characters, all DC, all Level 50. +2600CP