Hi,
I've just finished integrating EditArea in the SLD style editor.
If you don't know what EditArea is, have a look here:
http://www.cdolivet.net/editarea/editarea/exemples/exemple_full.html
SLD editing has never been so pleasing 
I would be happy to hear some reaction to this. Too slow? Too big?
Like it, don't like it?
Ciao
Andrea
PS: I'll back port it once we release 1.5.1