For the bed wiring I used a 15mm "plumbing spring" - the tool used for bending copper tube. It looks like stainless and has a nice finish. They are dirt cheap on Ebay. I printed a couple of clamps.
For the x carriage, I had a lighter 8mm stainless spring specially made up, following a suggestion on here. Relatively expensive though. I used a UK company.
http://www.testedspring.co.uk/home.asp