These Power distribution boards are dead easy to make, including a fuse per line to suit your accessory, a LED, a volt meter, even a switch per line if the box had enough surface room. Here are some pre-fab units used for RC modeling:
http://www.rcaccessory.com/12vdcpowerstrip.aspx
http://www3.towerhobbies.com/cgi-bin...?&I=LXUDR0&P=7
A simple one:
http://www.siriuselectronics.com/ind...roducts_id=453