XBMC is currently not a very good DVD player. It is very buggy and very incomplete. You can trick your wife however
Make a duplicate of your xboxdash (the official, and run a region free patch on it, then utilise tools discussed in the Xboxdash mod forum of this board (or maybe
http://www.xboxdash.net) and change the standby image of the DVD component to look like the XBMC background (also add text saying press play to resume the movie or stop to return or something similar) and also change the code to open up a xbe file when you press stop when it's in standby mode.
Set that code to open xbmc.
Then in xboxmediacenter.xml change the alternate dvd path to the modified xbox dash (keep it in C:\, just as dvdx.xbe or whatever, you'll also need to duplicate the supporting files and hexedit it to use the duplicate) and so whenever you insert a dvd with dvd autorun enabled or press the play dvd button you will launch the dash.
Read all the topics for information or if you're really stuck PM me.
It's crude, but gets the job done.
Morien <
