I've read all the posts, and I'm not really finding the information I'm looking for. I have a 66 Malibu with 18" front and 20" rear wheels. I'm trying to convert to slotted and drilled disk primarily for the look, while staying under $1,500. Here's what I'm trying to fingure out.

I've read where people converted to 70's era disk, but I'm afriad the small 10" rotor will look funny with the large open wheels I have. What size rotor will actually be enough stopping power for a daily driver/cruiser?
Can I mix rotor sizes? was thinking 12" fronts and 13" for the rear, just so the porportions were similar
Can you get a single piston solution for a 12" or a 13" solution?
Are there any kits I can buy that already have all the parts? Everytime I call CPP or SSBC, I get different answers on product availability and cost. They always want to push me up to a 13" 4-piston solution for pro-touring, which is not what I want.
Any help is appreciated.

For your price range, you might want to look at this kit (http://mattsclassicbowties.com/contents/en-us/d1284.html). It is 11" discs, but they can be drilled and the caliper powder coated which will give you want you're looking for: good look for a few bucks.

As for mixing disc diameter, the answer is yes you can, but if you're asking the question, you shouldn't do it on your own and ask a pro. Using different front & rear rotor diameters will alter the F/R brake bias (which can be compensated by other means like changing tire diameter or caliper piston area).

As for the minimum disc size, it is not smart to go below 11" diameter (That's OEM dimension).