Get a cheap 400w HPS ballast, a LumenMax Reflector, and a Phillips mastercolor 400w lamp. Phillips Mastercolor has beautiful color rendition, which is excellent for showing off your bonsai plants, and it's a fantastic grow light as well.
I think HTG supply sells ballasts, or if you're on a really tight budget, buy a kit from businesslights.com, and make your own case, but that's only if you're really handy. Ushio pulse start metal halide is also an option, but that's more for industrial growing.

Here is a link that might be useful: Mastercolor lamp source

Full-spectrum artificial lighting works best on plants less
than 2.5 feet tall. The blue does not penetrate the canopy
very well because it doesn't bounce as well as the red.

If you plant is substantially taller, I would recommend side
lights as well. Probably multiple 100w CMH, with horizontal
400w CMH overhead.

I grow nice bushy cannabis plants between 3-4 feet with just HPS, although lately I've supplemented with MH. I'm thinking of setting up a nice CMH garden, to grow them up to about 2.5 feet, after that let HPS take over. I don't like the idea of side lights at all - not really practical, and not needed with proper garden design. HPS is very rich in the longer wavelengths that penetrate the canopy really well. My plants grow really well with no sidelight, but that may partly be because the sides of my garden are completely enclosed with mylar, and sideways light gets reflected, and in effect, accomplishes the same as your suggestion to put lights on the side - the better way to do this is like in my garden, line the sides with mylar, and the plants get plenty of light on the sides and in the base. I have a 3 x 5' garden, running 2 x 400w HPS +- a central metal halide.
This is sufficient for 15 immense cannabis plants. Sativa.

I'm looking for a 600w Electronic/digital ballast. Silence is golden.. I like that Lumenmax hood. It looks like it is for a 4'x4' area. that would be a small for a 600. Does a hood make that much of a difference? I read a bunch of information on bulb difference, is it that big of a deal?
Thanks

I run all regular magnetic/iron ballast and I think it is the 1000w that's noisy, 600 and 400 hardly make a sound at all. Lumenmax is a very nice reflector, but why not use the reflectorized HPS (Gavita type) from HTG supply - you'll have the most ideal reflector available, the lamp will be out in the open and the natural ventillation will help keep it cooler, plus that lamp puts out 95,000 glorious lumens. Both the hood and the bulb make a huge difference. It's just my impression that for a bonsai you don't need those huge lumens, it would just be overkill, and that amount of light, 4000 lumens per square foot might actually be injurious - that type of intensity is more for growing a crop, like cannabis for example, or a nice huge crop of peppers or tomatoes. Lumenmax is an absolutely wonderful reflector, the 400w iron/magnetic ballasts that I have only make a little tiny humming noise, I've never experienced any of the annoying hum that you hear people talk about on internet forums, UNLESS you are living in the same area as your garden is, in that case silence is golden and I would agree with you buying a solid state ballast, and the ones available on ebay, in my experience work well - otherwise they would be getting bad feedback. However, Pulse Start metal halide ballasts are generally ONLY available from aquarium places, and I would really believe you would be extremely happy with a USHIO pulse start lamp that has very nice maintained lumens, very nice initial lumens, and one 400w lamp would be plenty for a 5x5 garden. Pulse start lamps are nice because you can leave them running continuously without danger of shattering or blowing up, and they have a re designed optimized cavity that burns brighter and tends not to get black like the probe start lamp. Sativa.

For the 600w digital ballast, I recommend a Pulse Start Metal Halide--way better spectrum than yellow-orange HPS. However
Ushio does not make this in 600w (nor to my knowledge does anybody else but Life Light). These Life Light Technology bulbs come in four different spectrums:
4K (cutting/seedling)
6.5 (most of the veg)
4K (last week of veg)
3K (most of the bloom)
10K (last week of bloom, for UV-B stimulation)

we've had people here buy digital ballast, and they failed to work with pulse start halide lamps. the only ballasts I've been able to find are for 400w PSMH, digital from the aquarium shop, and iron/copper/magnetic from business lights dot com.
Also, try to find a lamp that runs in the horizontal position - I have only been able to find horizontal 400w PSMH, not in any other wattages. Sativa.

I gave a nice scientific link showing how to convert the spectrum of the lamp into plant lumens. Human lumens are centred around yellow, the eye is very sensitive to yellow, but very little to blue and red, whereas plants soak up blue and red very well. However, yellow and red photons are much more effective in photosynthesis compared to blue.
The scientifically based paper shows HPS is much better for photosynthesis than metal halide - many more plant lumens per watt. Study the article, it explains everything, and then make up your own mind. Sativa.

Here is a link that might be useful: Actual scientific article that explains how a plant looks at your lamp, and how effective each different wavelength is for photosynthesis.