Thanks for your detailed description! I wanted to map the mouse buttons to abxy as well, now I don't have to fiddle with this, you already did ;) glad I could help a little.
//edit: imho it's worth an entry in the 'tipps, tricks, tweaks'-thread
It should be possible to reload the .Xmodmap per command "xmodmap .Xmodmap" or in our case "xmodmap pndXmodmap". edit: Run this command in the folder where the pndXmodmap-file exists.
I don't have my Pandora yet, but (in case you don't care to much about cosmetics) may it be possible to 'fix' the crack with some sort of instant adhesive to prevent it from getting worse over time? That would be a solution for me.