Bad news: We still haven't got in those new servers.
Good news: Things are progressing. Sometimes backwards, but mostly forward, we're now in contact with almost a dozen vendors. And we're still working with our normal vendor, Silicon Mechanics, trying a bunch of different combinations of machines. As a result, we're probably going to get 6 new machines instead of just two.
Also, we've given up on waiting for the servers and we're starting to do some work to make the site faster, at least until we get the new servers. We're rearranging users and resources, upgrading software and hardware, moving inactive users to the database cluster with larger, slower disks, etc. The performance benefit wouldn't normally be worth the effort, but in our case we're pretty desperate. Some of the work we're going to be starting here will benefit the new servers later anyway. (Details are outside the scope of this post.)
Much love to Silicon Mechanics, our loyal vendor, for going through all this hell with us. They're working on three separate configurations for us (Xeon EM64T, AMD Opteron, and Itanium) and kicking ass dealing with their dozens of parts vendors and keeping us informed of product availability, faults, etc.
No need to recommend SPARC, POWER, or Xserves. All have been researched, as well as priced.
I'll post more when I know more.
Free users, my apologies again for the continued suck. This performance is an embarrassment.