Hi Guys, i got here in the end, sorry to whoever PM'd me asking me to post here..
And yes, in answer to your question Kath, yes... We provide just such a service you are looking for.
www.1plus.net
You will have full control, you choose what banners you wish to display (from whatever source) and whatever news skin for your mini sites you want.. For this service, we load the house banners once every 10 pages views - and thats it.. At the moment, we are only providing two different "news" pages, but more ideas are in development.
If you check out
http://WiMax.tv, it'll give you a good indication of what I was trying to achieve in building this site.
Site is live for about 5 - 8 weeks now and we already host just under 10,000 domains, serving 15,000 to 30,000 page views a day and 200+ users.
Hope that helps. And once again, sorry for the delay in visiting this thread.