See Challenge # 112. Rohn's expansion. I picture old, non-golem creations being repurposed for new uses.

Ooh, very nice. I like our flavorfully and mechanically. It's a pity that it costs so much, but development would very likely Nerf it just that hard.

Huh. I get the impression it could come down more. It is, after all, asking for 100% artifacts. Exiling 12 artifacts in a normal game seems daunting, and that didn't even break the card, considering Gilded Lotus might be fair.

That said, an easier way to balance this card would probably be to make it a target. Instead of putting land tokens into play, it could just accumulate charge counters and tap to add mana equal to the number of counters. A single Shatter would probably stop it from being busted.

Yeah, Conversion Chamber only asks for one artifact from graveyard (plus time and mana, of course) to give a 3/3. I'd take a similar route with this, to be honest: something like

­, , Exile two artifact cards from your graveyard: Put a etc

Or following jmgariepy's suggestion:

­, , Exile an artifact card from your graveyard: Put a charge counter on ~. ­: Add to your mana pool, where X is the number of charge counters on ~.

I dropped it two exiling two artifacts and made the land an artifact land (this was done for flavor purposes). I didn't want mana to be pumped into this card.