Thanks to Planet Debian and Jan Wagner's post about dkms I learned about the HP DL160 G6. This 1U server can support up to 192 GB of RAM.
Looks like HP is recognizing the power of virtualization!
Comparing this to the microservers that Intel recently announced, it appears that the two companies are taking different strategies to high density, energy efficient computing. Of course, HP and Intel aren't exactly competitors. Many HP products include Intel chips in one way or another.
Both solutions use efficient power supplies and low power processors - a must for today's hosting providers. It not only makes good financial sense, it also makes for a good marketing pitch.