I think your requirements are a lot easier to meet than some of the requests we have dealt with in the past. As you can see vBulletin runs on our platform and we don't have any items that I am aware of that would break vB functionality.
You definitely have access to .htaccess and mod_rewrite
Support is also not a problem, we have typical first response times of about 30 minutes and most items are resolved within the hour. More time is required for complicated tasks but it is extremely rare for something to be open at our helpdesk for more than a few hours. We definately beat those hosts that have 1-3 day response times if that is what you'd like to hear
So yes, come try us out and see if we will work for you. There is a 60-day money back guarantee so that should be plenty of time to decide if we will work out for you.
I suggest a "pro" plan for vBulletin hosting especially if your boards are active.
Let me know if you have questions.