Two other options:

1. Make the trailer a low-resolution trailer, and put a tag that says that (something like "low-res preview. Members enjoy 640x480 1Mbps streams" )

2. Get another server with dirt-cheap bandwidth somewhere and host the trailers on that server, but host the rest of your site on your regular server. That way, if you have reliability or bandwidth problems, the whole site doesn't go down or get slow. Bonus is you can use the rest of the bandwidth on the cheapo server for galleries or whatever.