Yes this is possible. It is a scenario –at least is seems appealing to me- suitable for accessing SSAS from machines that are not in the same domain as the SSAS. SSAS understands windows users only (there is no such thing as SQL Server Authenticated users). So in order to access a SSAS instance you should either be a member of the domain SSAS belongs to or use a pass through logic via local accounts (i.e. use local SSAS machine account with the same username & password as your own).
However there is another option – also suitable for SQL Server.
You may use the msmdpump.dll as the conduit for your communication. Just create a web site the “exposes” this dll and use a connection string (from your office client not a from a browser) like this /msmdpump.dll">HTTP://<SSASMACHINE>/msmdpump.dll .
Here it the process (IIS 7 or higher)
It’s pretty easy to do and it can give accessibility to office clients outside the SSAS windows authentication territory. Particularly useful when business people would like to put their hands on your dev/test environment to test cube data.