according to vleds, 212s and 578s are the same bulb. wonder how your maps are the 212 festoons though? oh well, i'm just going off of what i've read.
green shouldnt be hard here is one example Green SMD 12 LED T10 Festoon Adapater Ford Dome light | eBay
i ended up using the cheap universal ones on this truck and so far so good. i bought the expensive ones from vleds and had no luck
I wouldn't shy away from the Chinese ones found on eBay - especially for an easy to get to location like map lights or festoons. The dash is another matter, since it's tedious to replace. I've had those 'cheapo" ones off eBay, and only one went out (early festoon replacement, 3 years ago). They're higher quality now, since SMD (surface mount LED) technology has gotten better and more reliable (my Mag Lite flashlight got the SMD LED replacement, and I cant count how many times it's been dropped - and no bulb failure). So, if a Chinese import is available in green, go for it.