[EricVanWyk]

The DSC's GPIO port has an extra power and ground pin to make it easier for you to do exactly what you are asking about. You can use a long single row connector to pick up as many signals as you want, plus power and ground.

Each pin is rated for 750mA. This may require you to use multiple pins if you are powering something beefy.

Note that the rules do not require the ground path isolation/redundancy strategy that Al recommends. In some cases, it is absolutely necessary for reliable operation. In other cases, it is superfluous. You must use your own judgment to determine what is best for you and then live with the results.

For reference, I do a bit of work with signals up in the low GHz range. Here, grounding strategy is critically important. On the other hand, I've gotten away with a lot of slop in the tens of MHz range. It all depends on the application. Also, when in doubt add bulk capacitance.

In my personal opinion (which you may ignore as you please), I think starred ground returns for the GPIO will have a negligible impact on noise, but I am warming to the idea of the redundancy.