I had this question after viewing Win7 x64 Host + Winxp guest + DOS Application Full Screen mode?
I admit to being a dinosaur that actually misses MS DOS 6.2 and loved Windows XP. The reason being that all my financial records are on Lotus 1-2-3 spreadsheets (dating to 1984) and I am not going to try a transition all of that to Excel. Lotus 1-2-3 ran beautifully full screen on my old XP machine but with MS refusing to keep XP alive I have transitioned to Win 7. The Lotus program will run in the XP mode of Win 7 but the screen is about postage stamp size regardless of how the Window options are configured in the shortcut. VMware is a bit better by allowing me to get to a 10" X 6" 20 line screen that is readable but I am still looking for a real "full screen" option.
"Aciddo" indicated that DOS programs ran full screen in Ver 7 of workstation after tweaking the options feature but I am using a 30 day evaluation version of Ver 12.5 and have had no success with the Ver 7 fix. I have tried adjusting the screen resolutions in both host and guest to lesser values but that totally scrambles the desktop icons causing consternation upon exit from the DOS programs. I have even tried DOSBOX but even though the screen goes to full the Lotus 1-2-3 program still is about 3" X 5" within the full screen.
There may be no viable fix for this problem but if anyone has ideas they will be welcome.