Thanks for the response Anna.  I came up with this same idea after I sent my original post last night, so I'm glad to get confirmation that it will work.

Having to manually delete the users seems crazy.  If those users are no longer attached to a portal, why aren't they automatically deleted?  It's basic data integrity.

While I'm glad it's at least "possible", it's still very disappointing that there's no better way than this "clone and hack" approach.  Migrating a portal should be as easy as clicking a button on the Host screen, generating a big export file, and importing that in to the new setup on a different server.  Anything short of that is a kludge.  Yes, it may be hard to program that due to the modularized nature of DNN, but I'm convinced that it could be done.  DNN is now at version 7 for heaven's sake.  It's time to start focusing on some of the basic plumbing needed to make this system truly world class.

Thanks again to everyone who responded.  Technology short-comings aside, the DNN community remains fantastic.

The method of duplicating the install and then deleting the portals you no longer need is the best way to do this from my experience it works perfectly and I have done it many times.  I can see it being a hassle if there are a lot of portals to delete afterward.  There is a great third-party module called "Bulk User Manager"  .  I use this module all the time, it is indespensible.

I have also moved portals using the template method.  If you log into your site as HOST and go to HOST>Site Management, then hover the the Manage action button on on the portal list module and choose "Export Site Template" and choose to include content, you might also get decent results.  I have done it this way twice with surprisingly decent results.  If you have modules that do not support export, then this method is not great.

As for being disappointed with the kludgy methods here, it seems to me you are asking quite a lot.  I personally am thrilled I can so easily do this, I recently started to set up a WordPress Multisite and to do the same process there is way more complicted than this.

I too have had 'surprisingly good results' with exporting to a template and importing into a fresh install. Around 90% usually, which for a small to med site is manageable. The template option for those who can't directly copy databases etc is a really good 2nd choice. Better than most other CMSs I have to say, as DNN is very robust around creating and deleting portals.

Caveat - the portal id number does change with the template option. Hence why I use cloning. But TBH the find and replace SQL isn't too hard. It's just a bit less reliable than the cloning option as far as knowing 100% of the original site is still there and working.

I *think* (and don't quote me on this) that the user issue is related to the way users are tied to the .NET membership? Hence why in theory it's possible to do multi-portal membership for one account (why this has never been a core feature I will never know!). That's the way it works for host users anyway, I suspect the difference applied to admin and lower level users has actually made the user accounts less manageable from a database perspective.

I second (or is it third) using Bulk User Manager to mass import or delete users. I've done 2000+ in one fell swoop before.