See Aeran Amphitheater.

This is a delightful approach to a rainbow land. I love flying rainbow Eldrazi Spawn.

I like this a lot more than its brother. I wonder if there's a better way to balance the token effect than giving the land a mana cost. We probably need a good land for the community set.

We'll need a rainbow land for Aer, and I came up with this last night. I wonder if it's appropriate. We just need to think of a suitable drawback.

Hmm. Mercadian Bazaar infers that you need to wait two turns before you can get one mana out... and even then, it's one color, doesn't put creatures on the battlefield that can block/always provide equipment bait (or be killed... but I think this is a net advantage.), and can be used to produce a mana per turn as per normal (the Bazaar can only give you a mana per every other turn, if you aren't saving up.)

­Fungal Reaches is a lot more lenient, I know. I only point out the bazaar because it's easier for my brain to process, and still seems 'fair', if not a little underwhelming. The key point is that this is a hell of a boost on most storage lands. In fact, if we were to play the "Most 2-cost signets can be non-basic lands" game (which may or may no longer be appropriate), then what do we expect to pay for an additional drawback when the non-basic land is Diamond Kaleidoscope (which still seems like a fair card to me)?

Maybe double Karoo? When it enters the battlefield, return two untapped lands to your hand? Not sure. You should be set back for all the versatility this card is handing you. I'd almost say "skip your next turn", but I'm sure a number of players would hate that.