@ Heretic: Shovel?!

For what it's worth, I've been tanking with the Exploration Retrofit. It's equipped with the full Borg set.
Forward: 1x Dual Phaser Array, 2x Phaser Array, Photon Torpedo
Aft: 2x Phaser Array, Photon Mines, Photon Torpedo
Sci Con: Emitter Array, Assimilated Module
Eng Con: 2x Neutronium Alloy, Field Emitter, Saucer Separation
Tac Con: Phaser Relay, Photon Detonation Assembly
Tac BOff: Fire at Will I, Torpedo Spread II
Eng BOff: EP to Shields I, Engineering Team I, EP to Aux I, EP to Shields II, Engineering Team II, 2x Reverse Shield Polarity II, Auxiliary to Structural III
Sci BOff: Polarize Hull I, Hazard Emitters II

He is talking about the Star Cruiser.

That's not a tank, that's a healer. Healers are nice to have in (organized) PvP (and a pain to even try in a PuG), but in PvE they're a liability to the extent of "useless"!
A Cruiser dealing 1k dps is not going to tank anything in PvE, all you do is heal the occasional AoE or random hit shot at you. And at the same time you're failing your group's optional objectives, or even the whole STF while you can't even kill a probe ...

To actually tank, you have to make things shoot at you first. And keep them shooting at you. That means even with maxed out Thread Control, you still have to deal at least half the damage that the Tac flying next to you in his Escort can deal. A bit more is usually not wrong either!

And to deal damage: You need at least one FAW (for AoE aggro), a second FAW or TS is nice, too. Dual copies of EptW and weapon power setting at max is mandatory!
Mandatory! Must-have!
After that, you can start thinking about how to survive the hatred - that's where constant TT, dual EPtS, HE, TSS, RSP, Aux2SIF, etc come in. Never, ever use an Engineering Team on a tank!

As for ships - pretty much every cruiser can do this. Well, except the Shovel (Star Cruiser), that one lacks the tactical options to deal enough damage, it's a pure support ship. If you'd wanted the shovel-look, a Mirror Universe Assault Cruiser does well enough.

Best suited: (Mirror) Assault for free or nearly free ship, Excelsior-R, Regent and Tac- or Sci-Ody w/ Ops console for Saucer Seperation for C-Store. Spent more, get more dps potential, and have more options for defense.
D'Kora is actually a Battle Cruiser already, and can outperform the Ody on dps easily, it's just a bit less tanky - but more than adequate.
Galor is probably the best tanking ship there is, if you can get one - you'll have to fly it as a shield tank though, with dual EPtS and TSS, which can be a bit close if you get hit by too many Shield Neutralizers in a row and your single HE is on cooldown and the Borg cleanse doesn't trigger, otherwise though you can't do better than that.
Sorted from worst to best, but all of the ships in the list are fine.