Looking for a Firewire cable tester

[Olivero]

I have looked everywhere on Google, Amazon, Ebay and Maplin for a cable tester. Will be used to test the speed of different firewire (800, 400) USB and Esata cables. Cables are used to tether high-end still cameras to computers, mostly for use in studios. A tester should be able to tell me which cables are toast and what is worth buying.
Should be an easy thing to find ?