I'm sure most decent power supplies have line filtering to minimize their noise from affecting other loads on the same circuit. I guess it depends on the type of power supply and the quality. But I wouldn't think you'd be any more likely to get a ton of interference by using a single AC input into your cabinet to power the individual items than you would if you had similar items, even in separate electronic devices, all plugged in to the same 15 or 20 Amp circuit (sometimes in different rooms in your house). Would be irritating to have to pull power into the cabinet from a separate circuit in your home though. You'd have to identify which outlets in your house are not on the same circuit (easy enough), and then run a drop cord from the cab to one of the separate circuit outlets, which is not ideal really.