Looks like the guys in #g2root and paulobrien have worked their magic.. There's now perma-root for the Tmobile G2/HTC Desire Z/HD. An automated version of VISIONary is in the works. See
http://forum.xda-developers.com/wiki/index.php?title=HTC_Vision#Rooting_the_G2
 http://forum.xda-developers.com/showthread.php?p=9115295
 
Or wait for an update version of VISIONary :)
 
Time to sell my Desire!