The BOM currently has a USB<->RS-232 converter on the parts list.

Cost as listed at amazon: 7.95+ $4.99 shipping = $13

I present to you the CP2102 single chip USB<->Serial solution:
[www.mouser.com]
$3.65

The next revision of the powercomms board might benefit from such a device. If the space was available pads for both RS-232 and USB connections could be provided and the builder could decide which one to install.

One problem is soldering this thing, it is a 5mmx5mm leadless surface mount part. A toaster oven reflow would probably be required at a minimum. This 28 SSOP may be a better option as far as installation but I have no experience with it.
[www.mouser.com]

-David

looks rad. that is definitely cheaper than a cable. perhaps we should start a powercomms v2.0 roadmap type wiki page to store all these ideas.