Russel Coker is looking for a Xen domU to rent for a new project he's going to start.
Using shared Xen hosting to lower costs is quite common these days. Steve Kemp does it and so do I (german). Prices are not that high that you can make a business out of this or earn your living from that, IMHO. At least not with a major investment beforehand. So, shared Xen hosting is mostly used to lower costs by sharing them amongst friends.
Just order a dedicated server, for example a dual AMD64, 4 GB RAM, 2x 400 GB harddisks, a /29 net and umlimited traffic (1 TB free at 100 Mbps, after that the bandwidth is reduced to 10 Mbps) for € 59.- and go for it. Get as much memory as you can get. I've found 2 GB RAM a little bit undersized, whereas I still have approx. 2 GB RAM unused/free for other domUs with 4 GB RAM, so there's some room for other domUs.
Currently I'm running 4 domUs:
Anyway, when someone would consider sharing a dedicated server with some friends, go for it! It's better for the environment as well, when some people will share the servers instead each of them getting their own one.