carlopmart wrote:
One question: will be possible to install OpenBSD 4.0 as a domU under a redhat/debian Xen based server???
Has nothing to do with OpenBSD version. Virtualization layer is mostly managed by CPU (CPUs w/ Intel VT Extenstions or AMD's SVM extensions)
Have a look at http://en.wikipedia.org/wiki/Xen#Hardware_assisted_virtualization_with_XenSo it's perfectly possible to install any OpenBSD version. (of course kernel has to support much of new hardware. Don't go for OpenBSD 3.0)