Based on the size and resolution of my Macbook (screen 11.25in x 7, resolution 1280x800), you should be able to get 1280 x 1024 resolution on a monitor with a diagonal size of about 14.5 inches. However, the normal size for a 1280x1024 monitor is 17in. Does anyone know of a manufacturer making a smaller size monitor for this resolution?
There is no such panel made. 1280x1024 is only made in 19 and 17 inch. I do not know why you need this specific resolution/size, so tell us a bit more. There are however notebook displays at 1400x1050 pixels that measure 14.1 or 15 inch. Maybe that is something for you. One model they were in is the Dell Inspiron 600.
Here you can order them as spare parts: