RapidXen provides highly scalable virtual servers on a computing grid through Xen virtualization technology. Technologies used in production include: Xen, Linux 2.6.26, ApplianceKit, LVM2 and ATA-over-Ethernet.
RapidXen enjoys a relatively stable environment, backed by engineers with a strong background in Xen internals and virtualization.
RimuHosting provide Xen-based VPS hosting. They specialize in providing hosting to web developers. They have a lot of experience supporting Java, rails, django, and zend setups.
RockVPS provides Windows or Linux virtual private servers running on Xen. Packages start from $19.95 and range all the way to high-end performance servers. Friendly staff and friendly prices.