We're big fans of tokumx. It's not perfect, but it's a big step up from vanilla Mongo right now (though the upcoming 3.0 changes with the new WiredTiger engine promise to catch up at least most of the way).
US residency is not a hard requirement - we currently employee Canadian and European developers in addition to our US-based staff.
If you hadn't seen it already, the TokuMX team is putting together a storage engine module designed to work with vanilla MongoDB's new pluggable storage system. This blog post[1] compares TokuMX to vanilla Mongo running their (experimental) engine. The short version is: TokuMX made some changes outside the scope of the pluggable storage system that give it the edge in some circumstances. An interesting read.
US residency is not a hard requirement - we currently employee Canadian and European developers in addition to our US-based staff.