I am searching for hosting providing you with both asp.internet (prefer .internet 4) and MongoDB. Anybody know any companies?
Mongo has a listing of accessible commercial service companies. Many of them are "private server" hosts. You are unlikely to locate anything outdoors of independently located servers that enables you to install Mongo on the system.
It is simply too new, it isn't like MySQL or SQL Server where lots of companies have just built separate farms of these things.
However, if you are already dealing with someone like "Maximum ASP.Internet" and you want to operate a Mongo instance "somewhere", you should use MongoHQ. They are essentially only a located database provider.
It might mildly affect performance, but let us be fair, if you cannot afford a VPS, you are most likely not too concerned about performance :)