Making your bike theft-resistant

Apart from the sensible suggestions there are other options.

Wire it up so that anyone who touches it is electrocuted. - Might leave you open to lawsuits.
Use those exploding paint things that banks use. - Not great on a bike with a nice paintjob
Build a GPS/3G communication device which is welded inside the frame. - GPS doesn't work inside though
Weld it to street furniture. - Time consuming.

hmn, am I the only person who actually been thinking seriously about converting my bike to a rolling stungun?