Hmmm i think you probably are better off with a piece of batton. At least you can cut that to whatever lenght you need. Looks very pricey too. Although saying that i am very interested in the festool circ saw with guide rail. Its one of those things that you dont really need but its nice to have.
The Axminster system, clamp guides and a simple straight edge all have the same drawback; the cutting line is offset from the guide. Where systems like the Festool, EZ guide and batten'n'backer win is you can line the guide up directly to the mark where you want to cut. Something to consider with these things perhaps.