I am looking for a new method of "editing" previously authored DVDs.

Basically I want to be able to added new footage to a DVD+RW at a latter date and change the menu to have a new thumbnail.

My current method is:
1.) Transfer DV footage to PC via firewire
2.) Edit in Premiere 6.5 (usually end up with ~5min clip)
3.) Encode DVD compliant mpg using the Mainconcept encoder
4.) Author a simple menu in a DVD+VR complaint software package

So far, the authoring apps I have used are:
Ulead DVD Movie Factory 2 - currently my top choice - Just doesn't allow for much creativity.

Nerovision Express 2 - complete garbage - never once was able to author a DVD without a crash

DVDit LE - Have not used much, because I wanted the +VR format.

My question is... Is there a better way (what software do I need) to edit my DVD+RW disk (menu and more footage)? I would like to use try other authoring programs, but i don't know if I could add stuff later. (I don't want to keep all the mpg files on my hard drive.)

Hopefully this makes sense.

Thanks for your opinions,

PS: here is a list of my "nice to have" features in the DVD authoring application:
The ability to creat buttons that go to another menu (not a movie clip)
thumbnails that show the actual clip moving
Intro movie (before the menu)
transitions clips between menus