You could setup an IIS site which will accept the requests for the subdomains and do a server side redirect to the correct subweb. I did this for our production website for our marketing guys. I used an ASP script so that I could have a single IIS site handle all 15 subdomains that they wanted setup. My script looked something like this.
HTTP_HOST = lcase(request.ServerVariables(“HTTP_HOST”))
IF HTTP_HOST = “site1.domain.com” then
elseif HTTP_HOST = “site2.domain.com” then