I found this, which seems to have launched mid-November
OMG! Simple Mobile
It has monthly unlimited plans from $40 a month. But says no contract, no credit check, and the T&C imply prepaid wth remarks about adding the next credit before 30 days are up.
Might be interesting for either long-term use, or for people there for a month who know they will make and receive a lot of calls. Needs a bit more research though, like what payments (foreign credit cards? or only bank details? or vouchers) they accept - I'd be cautious about a regular credit card for someone who does only want it for a month
Third party comments on launch range from guarded welcome to overt scepticism ...