Is there a program that converts VGASPECx.dat files into BMPs?
Do you really need one? After all, I already released the original VGASPECx as bitmaps (it's one of the posts on this thread). And the new ones you created will have come from a BMP anyhow.
What will happen though is, once I put color reduction in place, I will probably have the program output the color-reduced version as a BMP as well as the VGASPEC, so you can do further editing on it (and remake the VGASPEC afterwards) if necessary.