Nothing wrong with the idea but results can be mixed. For starters you can use heavy duty ie high amp cable from a local diy supplier. I made one up for my sub as needed a specific length and wasn't up for major expense for a custom length. Purchasing the iec plug part is not as easy though. I got mine from Russ Andrews however I think Maplins do them now as well. edit:
markgrant to be honest I would just buy one of his unless you need huge lengths
I can see this thread heading the way all mains ones do,,,,,,,,,