Excellent Hack - fantastic.
[high]* trilOByte clicks install
[/high]
One problem though, I inseted a category as a sub category, when I wanted it as a parent. I tried to move it and got a nopermission error (I'm primary admin, group 6), every attempt to acces thereafter and I get nopermission (I have permissions set to a -ve value). I deleted the category (catid = 3) using phpMyadmin (does only having catid's 1,2,4 cause a problem?) and everything else seems to work OK. I dont know why this happened, just thought I'd bring it to your attention.
Thanks for a great hack.