This Lurk ability... I like this ability. It makes you wonder if Wizards has thought of this yet, since so many ccgs operate by allowing you to use any card in hand as a 'land'.

Wizards most definitely have thought of this ability. They playtested it for Zendikar. In the end they killed it for rules reasons, and I still don't really understand why. I believe the rules could handle it fine if there were two kinds of face-down permanents. I suspect in fact it's not so much actual rules problems as potential for abuse in Legacy or Casual when someone has 2+ Lurking cards and 2+ Morphs. But really, how often would that happen?

It also featured in the excellent custom set Verdia, by fallingman. There it was called Earthform. I think it's an ability more people should use, as it's an excellent manasmoothing mechanic, as an approximation to the Dakkon Blackblade vanguard ability, which is an official rule in several later WotC CCGs like Hecatomb.

It's possible Wizards nixed the mechanic because it has so much depth. Morph takes up half of the Onslaught block, and Lurk could end up on a very high number of cards. With Traps, Allies, Landfall, and numerous non-basic lands, Zendikar seems complete enough... why waste a block identifying ability on it?

That, and Zendikar is a fast format, which does a good job contrasting it to Rise of the Eldrazi. Lurk, by it's nature, is a slow mechanic. Once I saw how the blocks were aligning themselves, I'd motion to have Lurk nixed, too. I'd be surprised if we didn't see this idea come back, though. I can't imagine it doesn'e have supporters in Renton.