Correct me if I'm wrong but there are two 6600 editors out there right now.

Nokia's Theme Editor
Microforum's Theme Editor

Nokia's theme editor is slow and has problems saving certain icon's when making a theme i.e.
conn manager
about (on top)
voice mailbox (on top)
speed dial (on top)
sync (on top)
log (on top)
Otherwise it's a fine editor but pointless for a full theme if you can't save icon's with it!

Microforum's theme editor seems to be a little better but has a few things that niggle away when doing a theme, such as..
Can't change the colour of the date in the middle of the screen
The bottom section (with the selection keys on) has to be the same for the whole theme. Looks stupid for the other pages like menu etc...

Anyone got any workarounds for these gripes?