For anyone interested in Assembly Language programming on the 6502/65816, this site has a full screen editor.
I downloaded a copy with the PDF manual for $25, or you can get a disk mailed to you for $35 I think.
It took some time for the owner of the site to get back to me, as he runs the site part time.
Seems to work great, but I haven't had much time to sit back and spend some time with it yet.
The site is a little disorganized, be careful to get the version you need (8bit vs 16bit)
They are both there, if you sort through the mess