I have just done my first new release of Minus4 in about 2-3 years!! Yes all these new features I keep going on about are have now been released into the wild. So if you head on over to THE MINUS4 HOMEPAGE you'll be able to download new versions of Minus4w, Minus4wsrc and the new Snasm.
The new Snasm also has a lot of 65816 assmbler support in it, but mre importantly outputs symbols for Minus4's built in debugger.
If theres any cool features you can think of, let me know.... Minus4 has moved from being the best emulator (now easily beaten by YAPE) to being the best for development - by far!
XeO3 is being developed using SNASM as the assembler, and Minus4 as the debugger. Yape provides more realistic playback, and the uploader provides real hardware downloading! All I really need to do is finish the remote debugger and we'd have a full devkit!!