There is a resolution hack for the Dreamcast emulator Chankast to run it in any resolution. It involves hex editing the EXE.

Vivanonno only runs at 640x480 and if you maximise the window, its only 'scaling' the 640x480 to whatever your desktop resolution is so it looks fugly.

Is there any method for changing the actual resolution to something higher like 1600x1200 in fullscreen?