What kind of digital camera do I need and where can I find it? See following criteria.?

I need to be able to change lenses for wide and medium range and telephoto. Camera should be 6-8 megapixel or higher. I need to be able to choose my exposure and aperture opening so as to produce special effects (overexposures, blurred backgrounds, etc.) I need to be able to attach a sync cable to the camera and use synchronized studio lighting instead of the camera's built-in flash unit. It doesn't have to be a top brand. A good-condition used or refurbished camera is suitable.

PC sync, while available on some of the newer DSLR's, is not used that much.

First, the new hot shoe's communicate with the new dedicated flash units.
Second, most of us using studio flash units, use radio controlled remote controls, similar to a Pocket Wizard, so we are not tethered to our flash units by a long connector.

That said, if you are willing to buy a shot shoe to PC adapter for under $10, you can use any of the current DSLR's for your purposes

http://www.adorama.com/FAHSPCA.html

However ... you will have to make sure your flash unit has a trigger voltage less than 12 volts (6v for Canon's) so you do not fry your camera's electronics.

That said, you can buy an entry level DSLR with lens for under $470 and buy a lens that will give you good Bokeh.

http://www.kenrockwell.com/tech/bokeh.ht...

The Nikon D200 has a PC flash connector.

Pentax K20D, Olympus E3, Nikon D300, D3, Canon 40D (i think), 5D, and 1d/1ds and Sony A700's all have pc sockets. Price ranging from $1,299USD on up to about $8,000usd

First thing - DO go top brand and don't buy a refurb. It's the old 'pay now or pay later' argument. Another thing - pixels are not as important as number of sensors. After 4-5 pixels it doesn't make much difference unless you plan on blowing up photos to mural size, in which case you will need ten or more. But compare number of sensors in the body - that's what gives you optimum clarity and depth of field, as well as special effect options. Of course, the more sensors, the more you're going to pay.

I'm partial to Canon, though Minolta and Olympus make excellent cameras. Canon Rebel is a good SLR, though it will not give you the speed and Flexibility for true professional quality shots. For that you'll have to pony-up for the professional D series. Lenses alone will set you back a grand or more.

It all comes down to what you want to do and how serious you are. Hobby - the Rebel or equivalent will serve you fine. Pro - you have to pay the big bucks. And I strongly recommend against buying off EBay or similar sites. Find a reputable dealer.