On the subject of machining a billet handle, yes it can be done.  Remember,
though, that the handle is the outer part of the lock.  There is a lot of
intricate stuff going on in the bottom of that lock concerning the return
spring, latch actuator, rotational stops, etc.  With enough dead presidents,
anything is possible, but I wouldn't want to foot the bill on machining a
handle from scratch.  No need to re-invent the whel, IMHO.
Steve Sandlin
http://www.steveslockshop.com
'84 Wolfsburg Westy
'79 Transporter
'00 New Beetle