I am not sure about all the devices you listed but in the past I have used Plastic 'P' Clips to secure power cords on the fixed configuration Catalyst switches (2950, 3550, 3750 etc).
There is usually a screw that secures the casing near to the power socket that can be used. I did a quick google and something like this is what I used:
http://www.diseastanglia.com/listing.asp?cat=588
Someone else who likes a neat & tidy installation :o)
HTH
Andy
