There was a desktop ACC that allowed you to pick 'any resolution' and it would scroll the screen with the mouse. It didnt really change the resolution if you somehow managed to connect a higher rez monitor, but it was a simple software solution to allow you to have a bigger desktop area to move around. Forgot the name of it.
I've heard of it, it was called MonSTer. Read about it in a Current notes article once, that's good if you want a larger virtual desktop if you're stuck with the smaller ST video modes.
It was one of solutions for running monochrome SW on color monitor/TV. Called mono-emulator. There were 2 types - 1 with res 640x200, where 2 adjacent vertical lines were averaged, and mentioned scrollable, with virtual res. of 640x400 . But all it has nothing with HW video modes. It simply worked in ST medium res.
Isn't that just emulating the high res mode on a color monitor? That's what Sebra does...