We currently use an old version of Stellent CMS (before Oracle acquired it) on our content site, and have a separate (custom from scratch) members website for member only features, and a Yahoo store for our ecommerce efforts.  I am pretty sure that DotNetNuke will be the replacement product for Stellent and eventually all of the others.  Since our main content site often receives burst of traffic that we cannot handle in house we have to host it remotely on a co-located server.  This is what we have been doing in the past and we plan to continue to that way in the future (unless very large pipe suddenly get reeeeally cheap).  Eventually we would like to get all of our sites consolidated into one site on a remote server under DotNetNuke.  My dilemma is this:

We would LIKE to tightly integrate our internal database with the content site, "members only" portion and ecommerce site. We have a product that we use internally called Aptify that serves both as a data management system and controls the business processes that use those data structures.

My options as far as I can tell are:

1. Expose the database server to the internet, but I just don't feel good about that no matter how securely it is locked down.
2. Create a VPN tunnel from the co-located box to our network, but I'm concerned about the stability of the connection and speed issues.
3. Create web services on a local web server that expose the necessary data, and have the co-located DotNetNuke consume them.
4. Create an internal DotNetNuke site that has all of the functionality that requires access to the local database and then some how wrap that content into the co-located site dynamically.

One of the things that concerns me the most is how we will implement an ecommerce solution that integrates with our internal inventory management system.  For most of the other stuff we can make something custom to handle this, but writing an ecommerce solution from scratch is a daunting task, and we will ultimately get a custom solution completed that is as feature rich as a boxed one.

Is anyone else out there using DotNetNuke on a co-located server with tight integration to a database server on their intranet.  What advice do you have for me?  What issue did you run into along the way.  What solutions did you find to be the best?

It seems to me that the content portion of the site and the data that is tied to these must be homed on the co-located machine to handle burst of traffic properly.

Any advice anyone is willing to share would be greatly appreciated.

your option 3 sounds most promising for me. last Year, we successfully implemented a solution for one of our customers to deliver documents and display data from an inhouse system within DotNetNuke.