With all due respect, WoTC will just print another set of lands. Why not just print these:


New Taiga

Land
Tap: Add R or G to your mana pool


No duals, no helping your Nightmare or retrievable with something like a Tithe, but still great lands for doing what you need done. Or you could print these.



Cold Taiga

Snow Land - Forest Mountain



You could even do this


Legendary Taiga

Legendary Land - Forest Mountain


for just one copy in play at a table.