I don't know for XP but there are several out there that will replace explorer.exe for you. I looked at them a while ago, read years, and I don't know the stability they would have. Just google something like windows replacement shell. Try different search strings.
anyway here is one I found with the string I gave you.
Sorry I don't remeber any of the sites I used to go to.
As a side note, if you are wanting to replace the shell why not change OS's to linux or something?