A general rule is if you are going to host more than 6 players it better be a dedicated T1 server. SH is a hog on processor power. I suggest you email various server companies and get some feedback. here are some links to server companies. Email their tesh support of browse their FAQS for info on the types of server components they use as well as backbones they use in major NOC facilities.
http://www.xgaminservers.com
http://www.ilangame.com
http://www.combatgamingservers.com