I found this article pretty interesting. It talks about implementing object caching with Aspects. While I haven't done anything using real aspects I have implemented a "CachedEntityProvider" that can be configured to cache the results of queries to the data store. I've only started playing with more advanced configuration such as setting the cache duration on a query by query basis, as well as providing more advanced options on how the query results (objects) are cached (duration vs. sliding expiration).
The implementation was a pre .net 2.0 implementation so it's not using the official "Provider" model but I'll certainly be looking into the potential for migrating it as I begin to dive deeper into the depths of beta 2. The only concern at this point is that the out of the box provider "goo" we get doesn't provide enough flexibility in the configuration. Last I looked it was passing configuration data via a Name/Value pair which would prevent more advanced configuration for per object / per query caching.