That's really weird. The hiss/buzz shouldn't be happening if they are all plugged into the same outlet. It sounds like something is wrong with that outlet. Could be something like the copper connectors between the top plug and bottom plug are broken and/or barely touching. Or it could be a loose wire connect on the outlet, or the outlet is not gripping the plug correctly. Maybe have an electrician look at the outlet?
As far as the power strip, that DIY one from Parts Connexion looks pretty good for the money. Be aware that the outlets used are just common 15 amp outlets ({nothing special), but it will allow you to use good internal wire. And you'll still have to get a separate power cord to connect this to the wall. You can go to local hardware store (or home depot) and get a couple feet of 12 awg solid-core wire (or stranded THHN). Or you could order a couple feet of the following Neotech 12awg Solid-Core UP-OCC COPPER Wire, PVC Jacket:
http://www.partsconnexion.com/wire_hookup_neotech_cu_pvc_sc.html
Look at the installation guide:
https://www.dropbox.com/s/ueiowanv5jqvtp4/triplex.pdf?dl=0
Examine the pictures carefully and make sure the black wire (hot) and white wire (neutral) are connected to the exact positions shown in the picture. You want to make sure the hot/netrual wires on the outlets are connected correctly (yes, this matters). If you use the Neotech, just put black tape around one wire so that you can use it for hot wire.
This DIY kit will allow you to upgrade the outlets in the future, if you want to buy something like Furutech FPX Rhodium.