<p>Has anyone managed to get subsonic or a variant working on Windows Mobile? We cant get it to work as it has a dependency on System.Configuration.</p>

<p>Any suggestions on an alternate ORMs that would work on a windows mobile device?</p>

Is the System.Configuration dependency the only issue?  If so, you could always try to get around it by adding that capability.  For example
OpenNETCF's SDF
has an OpenNETCF.Configuration namespace that mirrors a lot of the System.Configuration namespace.  You might be able to eitehr modify subsonic to use that namespace, or modify and recompile the SDF's assembly to use System.Configuration as a namespace.