Huzzah!
I was going to convert a mini to start with, but sadly they are quite rare in Perth (particularly an old roundie like yours), and probably too small for my requirements anyway.
Good luck! I'll keep track of your progress, it'd be great to see an electric mini on the road.
Oh, and you should visit the Ausmini forums, there is one other guy converting a mini in the eastern states, and one guy in England who has converted a mini ute (I think it was)
http://www.ausmini.com/forums/index.php
Good luck!