THe purpose of CacheLoader is to persist your state. As a result, the DB table is very simple since it is a blob. So I don't understand why you need to front it with Hibernate?
Well what I've been thinking is creating a cluster of JBossCache instances which each in turn are attached to a database distributed over a large number of LAN and WAN machines running almost as a grid with some webservice front end.
In front of the cache I want to put some silly POJOs for a login service (for example - don't really want to do this). So now when my authentication manager says - "hey cache, give me this guy /company/foobar/user/blah", the cache will say "hmmm... I don't know this guy, lemme instantiate this object and insert it in the cache. When this happens I'm looking at the CacheLoader as a way to short circuit this entire process so when the cache miss happens, the CacheLoader is passed the information (which would pretty much be the key in this case) necessary to instantiate this object into memory and insert it into the cache.
So I'm looking at a hibernate layer as a way to bring the POJOs into memory so they can be inserted in the cache and that's what I was looking at the CacheLoader as doing.
Hopefully that made more sense then what I said before and that I'm not using the product in the wrong way.