Just this minute I implemented a solution to listing hybrids in my spreadsheet. It was someone else's idea to put hybrid cards under each color,which is a good idea. I never did that because then the numbers would be off, such as the number of cards in the cube. So what I did is list the hybrid cards a third time in the multicolor section, and count them up in a cell there. Then on the start page where it has the number of cards in the cube, I subtracted the value of that cell. Now this also gives me a more accurate reading of the number of cards in each color. It's way better.
Anyway, this is all pretty much the least interesting part of cube design, but I thought I'd share.