Not the best suggestion but a shortcut to "START /MAX mmc.exe file.msc" may work... or creating a custom MMC snapin panel, (just run mmc, file, add/remove snapin) then saving it and shortcutting to it with Maximize option set on the shortcut might do it as well. MMC is well designed but seems like MS needs to spend some more time on the UI options it has.
Thank you for your response. I did try this prior to my post; I was able to get GP Edit to launch but it still was in a 'normal' window. Tried again after your repy and same result. Will try the other suggestion.