What I think would be particularly neat for the home is that I like my 16:9 for HD, if I could take off the top row and add it to the sides for cinematic widescreen [no or less bars on top and bottom] that'd be really cool. Watching old 4:3? Take a couple columns of and pop them on top.
As far as the math-
For 16:9, you could do 12x7
For 4:3, with two more blocks you can do 10x8
For 2.35:1, 14x6
If each block was an 8" diagonal, then with 84 of these blocks you have a
79" 16x9 TV, a 72" 4:3 TV and an 86" 2.35:1 TV all in one.