NoSQL databases that officially support MonoTouch
c#-4.0, nosql, xamarin.ios
Solution
According to http://nosql-database.org/ there's siaqodb. Note that others might support MonoTouch without being mentioned in that site.
Edit: a few more clicks shows that HSS Database (from the same list) also supports MonoTouch.
You might also want to look at which ones support iOS (e.g. with Objective C) and see if bindings are available (or write your own).
Problem
I am having trouble finding a NoSQL databases that officially support MonoTouch via a local DB on the device. If their are, could someone provide a list of them here.