from what i know...
matamp USA took custom orders for green, whites, reds, blues, etc. all variations on the old oranges. they were made by matamp in the UK for the US distributor. these are what sleep and every stoner rock band played. matamp always sold fully-customizable everything based on a few basic platforms. you could get your band's name printed on the faceplate, or a matamp logo, or whatever else in basically any color you can imagine. look at the gallery of
www.matamp.co.uk to see a few examples.
matamp got tired of the USA guy selling these a super badass high-wattage overdrive earkillers, where people would run them at insane volumes and under major stress resulting in problems, so matamp reduced their published wattages. the 120w is now called a 60w. i asked jeff at matamp and he said "it's the same amp, we just had to reduce the wattage rating to keep you americans from trying to run them as bass amps and blowing them up."
so the US guy, who had been selling balls-out, bong-huffing power didn't like the new direction of matamp and matamp didn't like the way their products were being marketed in the US. so they stopped using their US importer and that guy started Electric amps. Electric amps are made by him and are basically the same as the green and other colored amps except that he is making them and not matamp. i think the same guy who does Electric ran that stoner rock label 12th records.
i'd get a matamp. not as many wild color choices, but for the money you can't beat their amps. i got mine for $1500 shipped to the US, plus it has my name engraved in it which is gay/rad.
it shakes the earth, man!