Oxford, sounds like you have lots of reading still ahead of you. =)

I can relate to your confusion as there is a lot of misinformation and misunderstanding out there. Hopefully I can help just a little, based on my own experience (so far) growing succulents with lights.

Where to purchase: Hydroponics stores, hardware stores, amazon/online. Some industrial supply companies may sell fixtures as well.

Size of setup: There are 2' flourescent fixtures available. They are a little more pricey than the standard 4' fixtures. 3' fixtures are out there, but the bulbs are quite expensive for what you get.

If you just want to light a single plant, you could probably get away with a very bright single CFL bulb and reflector.

Light colour: For growing succulents, 6500k daylight spectrum is quite good. No need for special blue/purple lights unless you are trying to do something very specific (unlikely).

# of bulbs: Depends on how many succulents/plants you own, how big an area you want to grow with, as well as your growing goals. T5HO lamps are quite powerful, compact, and easy to customize spacing if you buy the fixtures separately.

As for how much you need, if you want very colourful and compact succulents, aim for something around 40W/sqft of growing space (assuming lights are 1-2 inches above your plants and you have a good reflector).

If your goals are just to maintain your Echeveria over the winter, you could probably do it with half of that amount of light. Of course, if you use less powerful bulbs or put them further away, you will need more of them.

As an example, here is my current lighting setup:

And here is one of my Echeverias growing under it:

Thanks, this is incredibly helpful.

No problem, anytime. =)