How can I limit the number of results AFTER sorting using HQL (and Oracle)?

This query:

FROM mytable WHERE startdate >= :start AND ROWNUM <= :maxResults ORDER BY lastname DESC

limit results BEFORE sorting.

Thanks in advance.

Your results can be treated as a plain .NET collection. Just remember that NH knows everything inside the collection it gave you. This should give you a new collection.
This will disable some of the smart things NH does with collections, though. For example, you can't do and expect NH to remove the item with ID=3. Only the "results" collection returned from the mySession.Find above would be able to do that.