Like this?
http://www.bulgin.co.uk/Products/IEC_Connectors/IEC_Distribution_Box-Panel.html
Essentially you're making a power strip. If a box of $7 power strips don't cut it for you, simply take a 4-gang steel outlet box, wire up and screw in four duplex jacks, then on one of the short sides, put in a wire clamp, shove in a 20A cable, put a plug on the end and drill a 3/8" hole to install a radio shack 15A circuit breaker.
Wire the breaker in the hot lead, wire all the grounds together and tie it to the metal box, then tie all the neutrals together.
Use wire nuts, use copper wire, use industrial grade outlets and this thing will last forever, even if it falls out of your truck.
If you don't care about UL listing, you can make your own box using 1/8" steel plate, weld it together, and instead of duplexes, purchase outlets like these for $1.20 each and cover the front surface of the box with them, spaced 3/8" to 1/2" apart so you have proper support and the cover doesn't flex:
http://www.mouser.com/catalog/specsheets/041504.pdf
Years ago in a home studio I made such a box with 100 outlets on it, tied to a 15A through-hole circuit breaker. I needed such a massive thing not because I needed more than 15A, but rather something to plug in the 300-500ma stupid ass annoying wall warts that everything comes with these days. So, I made a huge box with one cord going to 1/2 of a duplex in the wall. The other half went to a "normal" power strip to which my computer was plugged into.
While it sounds strange, one big box with many outlets is by far better than daisy chaining 6 outlet power strips. If one of those switches or breakers flip midstream, you spend an awful lot of time searching through a pile of crap on the floor.
