Jeff, one more observation.
I've just tried uploading through a secure connection, using WinSCP. The same thing happened, although the connection stayed up for a minute or two, but was eventually dropped by the DH server. I realize I'm physically on just about the other side of the globe, but I've never seen a server actively drop connection in this way, where "never" means 7-8 years I've been using remote shell accounts.
I'm quite worried, because I absolutely love what I've seen of the setup and tools DreamHost provides - yet atthe moment I have no way to upload even a single file if the file needs more then 30 seconds to get through.
(I could only test www access before signing up, of course, and it was excellent; and ping times were consistently better than pings to my previous provider, located in the UK)