Danny,
I think that you are getting the message from the professionals here that co-hosting is the answer.
I completely understand your reticence about getting involved, it seemed to me to be a big step when first proposed by our Technical Director a while back, and if you don't know your way around the subject and spend most of your time pointing a 737 in the right direction I can see the temptation simply to build on what you've got.
BUT we've never looked back from the decision to co-host. It literally reduced our costs, cos we had been paying a fortune for a T1 trunk, and the co-hosting actually cost £4k a year
less and we never have to worry about the line going down, because we are on the UUNet/3Com trunk...the biggest in the world.
As your own stats show, you have a wealth of IT pros on the site. I cannot believe that at least some of them wouldn't give you free advice and even physical help to get this going in a co-hosted site.
I would bite the bullet (but do not, I repeat
not take it with you through security
) and start the process to investigate the co-hosting option.
...or ignore me...that's cool too..it's up to you mate...
Will