I could use 36" or 48" surface plate, but no one makes one that's 8" or 12" wide. A wide plate of that length would be too heavy for my uses, such as guitar fretboard truing.
Can a surface plate be cut the long way without destroying its accuracy? Are there internal stresses that would just ruin the accuracy?
I had thought it could be cut by a water-cooled diamond blade in gravestone or counter top shop.
I was also thinking that splitting a 24" plate into three would yield 3 plates that could, hypothetically be trued together, if need be. The pieces would still be over a hundred pounds but could slide on find grinding compound or cerium oxide, such as the telescope people use.