I'd concur. Some panels on the existing cabinet might have to be blanked but 4 pigtails with NEMA 14-15p plugs and 4 NEMA 14-50R Rece3ptacle s- basically an electric range set up - would seem to run in the $15-20 range each component - so under $150 for all of the parts - plus pipe and wire and qualified install. I "think" Steve Terry would concur. I agree emphasizing the necessity to find qualified personnel to do the installation and modifications. Probably not one or two useable LED units - and they require jumpers and other wiring.
The 30 amp "Dryer" plug/receptacle is about the same price as the 50 amp "Range" plug/receptacle. In fact, often it is sold as the same plug packaged with both blades. Beware of one thing- The "Range" plug/cable set, such as you would buy at Home Depot, is not suitable. This is due to the fact that the cable is a light duty plastic AND although the two hots are gauged at 6, the ground and neutral are gauged at 8. I am not sure why it is listed as UL approved, but I suspect it may come under the "whip cable" exemption. In either case, use the plug assembly with 6/4 SO cable.
As for the connectors not being permitted for stage usage, I am not aware of that and have seen plenty in use. (There may be local rules that prevent their use.) Pin and sleeve connectors are preferable as they are locking, whereas the range plugs are not. Unfortunately, pin and sleeve connectors are also $$$$!
One annoyance of the standard "Range" plugs are that they exit at a 90, so they are problematic in some cases. However, in this case, it is probably an advantage.
One last thing about cams- (This may have been covered before.) They are considered a "tool-less lug" so the same rules apply to plugging in a cam as do to a direct tap. (See- http://www.controlbooth.com/forums/lighting-electrics/18977-cam-turn-arounds.html#post173586)
This is why multi-pin connectors are the way to go.