Actuall, instead of coding one in- someone can make an already coded default.xip and just tell ppl where the XBMC folder should be according to the edited default.xap.
Make multiple default.xip files with different xbmc folders (i.e. one for retail 8GB HDD (E drive XBMC) and another for larger HDDs (F drive XBMC).
I'd do it myself, but im lazy and have no place to upload w/ a decent bandwidth.
Someone try it out!!!!