If you are near Milwaukee try http://www.altgarden.com/site/retail%20stores/stores.html

If you aren't using a digital ballast you may need to buy a ballast that works with CMH.

high pressure metal halide lights aka ceramic halides are meant to be used with core and coil SODIUM ballasts, not digital ballasts, which would void the warranty on both bulb and ballast. this said, they're almost as good as the sunpulse pulse start bulbs, which are designed specifically to be used with true-digital ballasts

Since I am slow and care full, I will ask straight out.
Is a CMH light the same as a metal halide light? I search for CMH and get very little, but find many metal halide ones.
In other words, the stores sell metal halide, but every one recomends ceramic metal halide (CMH).

CMH lights are meant to be used in an HPS fixture/ballast. They are a hybrid between HPS and MH. You can't run a CMH in a MH system.

So, I have an interchangeable ballast between MH and HPS. I grow bonsai and want vegetative growth. Would MH or CMH be the better choice? Not just for the plants but energy consumption too.

you are better off getting the pulse start venture metal halide uni-form with very wide spectrum light which looks just like natural sunlight. it has very high lumens and the spectral output is excellent for plant growth. i order mine from plantlightinghydroponics in indiana. they are very good. go on the venture site, pick the lamp you want and send them an email asking for it, and they will get it for you. ceramic metal halide is now quite old technology, and the uni-form pulse start is the way to go.