If you decide you really do need to run 20' power cables it's possible to very easily make them up yourself. You can create a shielded power cable for about $75 with some of this:
Cable
One of these:
Male plug
and one of these:
Female plug
There's no soldering involved and it shouldn't take more than 15 minutes to do.
Cable
One of these:
Male plug
and one of these:
Female plug
There's no soldering involved and it shouldn't take more than 15 minutes to do.