I have been working on producing a method to update the kernel \drivers within the Altiris DS PXE image. Here is my how to for compiling a new kernel and integrating it into bootwiz.
Update: I have recently had problems with the latest HP DC 8200 elite desktops that are using the new Intel Q67 express chip sets. from what I have found you need to be using a quite modern kernel 2.6.38/39 ish. I personally have had success with the 2.6.39 kernel. This was not spported in the linux boot that was relaesed for DS SP 5.