In essence this is a followup of this question. I'm beginning to feel that I should give up the whole idea, but I'll give it one more shot.

What I want is pretty much like a DB transaction. It should track my changes to the DB and then in the end allow me to either commit or rollback them. If I insert an object, I should get it back in my next (appropriate) SELECT query. If I delete it, future SELECT queries should not return it. Etc.

But there is one catch - this transaction would be very long running. It would start when the user opened a form (I'm talking about Windows Forms here), and the commit/rollback would be when the user closed it(with OK/Cancel). So it could take anywhere between seconds and days. This requirement rules out a standard DB transaction because that would lock the tables/rows it touched, and other users wouldn't be able to use the system. Also the transaction should not commit ANY changes to the DB until it was really committed. So if one user makes some changes, others don't see them until OK button is hit. This prevents errors in case the computer crashes or is disconnected from the network.

I'm quite OK if the solution puts constraints on my model (I'm using MSSQL 2008, btw). I can design the DB/code any way I like. I'm also fine with the idea that a commit could fail because someone already modified one of the objects my transaction touched.

Is there anything like this? I looked at NHibernate.Burrow, but I'm not sure that that's the thing I want.

Added: It's the very beginning of the project so I'm not tied to NHibernate. I started out with it but I can still change easily.