You can buy an album in 12x12, 10x10, 8x8, 6x6 etc. Lots of choices. There are several options for Wide-Carriage printers that do up to 12x17 paper. You can also do pro printing at 12x12 or 11x11 (much more reasoanable) then mount the 11x11 on 12x12 cardstock and put in your book. There are also hardbound albums that do 12x12 for special things like weddings, baby's first year, etc. GORGEOUS! And not much more than printing the pages all separately.
Go to your computer store and ask to see all the printers that do wide format. Especially if your exisiting printer is old, upgrade to a big one!
But pro printing is cheaper for most things except 12x12 (but you still need the big printer to do 10x10 and 11x11 at home)
Have fun, hth!