There is already a Hosters' Forum. Would that be a good place to jump in? Or do we need something else? I see that the hoster's forum gets little traffic.
I have a dedicated server via Power DNN and currently have about a dozen DNN installs on it with anywhere from 1 - 30 portals on each install. My original goal was to use DNN to host a large number of sites (100 - 1000) per DNN install and I still would like to do that for specific vertical markets. I have recently started just putting some new customers on their own DNN install. It depends on the nature and importance of the customer. Not sure how long I will go down that path, but it does make it easier to do certain things for some high end customers that may want several sites of their own. I am also using the DotNetPanel for my control panel and it has turned out to work really nice. I use SmarterTools for mail, stats and help desk. Gene6FTP rounds out my offering.
I have been around since DNN 1 and currently have all my installs at 4.4.1. I did not upgrade any of my DNN 2 installs to DNN 3, I just recreated them from scratch. That was mainly due to the breaking changes and the fact that I had heavily built my sites around the Magic Gadget module...which was so great, but the developer just disappeared into thin air. That taught me a huge lesson early on regarding working with third-party tools and getting source if at all possible. Anyone ever figure out what happened to John LaRoche (I think that was his name)?
I would definitely be interested in working with others on determining really how scalable DNN is. I was getting a lot of memory errors and my sites were running slow in Admin mode. But I only had 1GB of memory. I upgraded to 2GB and now my SQL server is not constrained and I don't get memory errors and sites are much faster in admin mode. I still think I probably have a few issues with some modules, but not many. I would like to upgrade my server, but need to generate the $$ to justify it.
I have another group of 4 high end servers with a load balancer at PowerDNN. I will be running only 1 DNN site on that (for now) and 1 large PHP-based membership site. I have two web heads, 1 MySQL and 1 SQL server. I am just now setting up the PeerSync software to do the two-way real-time synchronization between the two webheads. Another DNN guy recommended PeerSync. At first blush it looks pretty good. So...we will see how that goes.
Count me in on any discussions and email me if you would like to swap additional contact info like Skype or Yahoo IM.