In this highly edifying post:
http://blog.hibernate.org/cgi-bin/blosxom.cgi/2005/03/11/
Gavin refutes numerous untrue statements about Hibernate, but, in passing happens to mention that "No Hibernate user has ever asked for support for concrete collection classes".

Well, consider this your first request! I have been looking through the updated versions of the proxy and property packages for Hibernate v3 which Gaven has mentioned are the extension point which enable this, but I'm afraid it isn't sufficiently obvious with the documentation there to figure out how to get this done. Could somebody supply a simple example of this technique? This could either involve some CGLib trickery, or else the manual creation of a new interface for the proxy with the relevant bit of "glue".

I don't want to get into the discussion here about whether this requirement is legitimate or not (e.g. "you should program to collection interfaces and not implementations") as I fear this would generate rather more heat than light.

Cheers,
Antranig.

Oops...

After re-reading Gavin's post again I found I had been misdirecting myself to the wrong packages based on other readings. After a quick browse of the source it looks like org.hibernate.collection.PersistentList & co is precisely what I'm looking for - please ignore post :P

Antranig.