All this sounds great.
But I would worry about allowing file attachments.
Isn't that how many viruses get through?
I've had the chance to look through the code for the file attachment feature. I won't go into details, but because of certain aspects of the way the feature is written, there's no way that an attachment which might contain a virus can infect the forum itself. The programmers thought of that in advance.
But, of course, there's always the possibility that downloading an attachment to your own computer could be another matter. However, common sense would probably dictate what you might download. It's usually not a good idea to download anything that's from someone you don't know or trust. And it's always smart to have a good virus detection program running on your computer at all times. In fact, just to be doublely safe, we could institute a policy whereby all file attachments on the forum will be scanned for viruses and shouldn't be downloaded until either Midnite or I sound the all clear.