scratch the jigsaw. I built my rails today and used a circular blace skillsaw. It worked great. You don't need a special blade, i used the same one for wood as i did the puckboard. It had like 1/2 inch or so teeth on it.
i haven't tried it, but i will be doing it tomorow when i make a couple rails. Just draw a straight line with a marker and keep the saw right on the line. If you can't do that then you must have polio or something