I'm running mergedfb on a radeon x850 (but have tested with twinview on a GF7900). If I set the horizontal virtual size to 4, I get an eight sided cube on each screen. Every other side of the cube shows the opposite screen.
Created attachment 10308 [details]
Screenshot of my zoomed out eight sided cubes.
Created attachment 10392 [details]
Screenshot, using twinvew, at two separate resolutions.
I have the same problem...
For those trying to get Cube Caps working, I noticed that if I set the following, the caps start work:
General Options -> Desktop Size -> Horizontal Virtual Size = 2
Once you've done that, the following happens:
1) You get 2 cubes still, but with 4 faces instead...... Almost there!
2) Even though you have 4 faces per cube, only 2 are usable :(
I've tried changing the other options on this plugin, but to no avail.
Appears to be fixed. Not sure when this happened, but there's now an option in the desktop cube settings for multi-output mode. Setting to multiple cubes works.