I recently picked up one of these XV-5050 rack synths on ebay, and finally got around to making some demos with it. My interest was re-kindled when considering that the XV-5050 has the same patches as the larger XV-5080, and all of these patches are included in the new Roland Integra-7.
Anyhow, this is one exceptionally cool synth. I snagged about 30 sounds for these three videos, sounds that for one reason or another induced me to add them to the XV-5050's "favorites" list.
I bought my XV-5050 on ebay for less than $300, as I recall. That was a great deal, but I still see them for $275-$350.