So I've been using GTD for a while now and think I know what I need for it to be effective. My perfect web solution would have:

ability to be hosted from my webhost
password access
GTDWiki style
iCal syncable
ability to send reminder alerts via email
customizeable style/interface
checklists

so far i have seen nothing that has all of this.
I like backpackit.com's check lists, but wish they had reminder alerts associated with them
i like zohoplanner but I want it hosted on my site

if anyone know of any solutions that exist out there, please let me know.

thanks!