Ultrium 4, where art thou?

We're starting to near capacity on our tape library at work, and I'm itching to buy a new system to augment it.  Ultrium 4 (or LTO 4) is right around the corner, but no vendor can tell me yet when they're going to have the drives.  Ultrium 3 is available now, but if I can wait a few months to double the capacity of my library and increase the speed of my drives by 50%, I'm inclined to wait.

We've been using Ultrium 2 for the last four years, and while it has worked well, a full backup of the servers I do backups for is now approaching 30 tapes, and storing and moving them is getting to be a pain.

First one to show up on my door with an LTO 4 library gets the purchase order...