If you used the front hub assembly offf of an SN95 car but changed the bearing in there so that it had the correct OD for the hub and the correct ID for what ever spindle you are using, you would have the tone ring needed for the front.
This is exactly what I had been thinking as well. I'm going to try to find a way to mount the rear rings on my 9" axels instead of using an 8.8.
As for soaring1's cost expectations, I spent a little time on ebay last night, here are the "buy it now" prices, which are always on the high end:
ABS unit: $45-50 (1 needed)
Sensors: $25-35 each (4 needed)
Front hub assembly: $50 (2 needed)
Rear exciter ring: $40 (2 needed)
Worse case total from ebay (minus shipping) is about $370. I'm bettting that you can do much better than that at a u-pull it yard, and all of the components would be from the same car (hopefully).
Obviously you need calipers, rotors, lines, and brackets and a prop valve. But if you're already doing a brake upgrade, then you've already planned on spending some coin. As bnickel said, if you do it yourself there's no labor cost. I'm guessing the grand total will be in the neighborhood of $1200 or so.
I'm just starting to buy parts, so it'll be a while before I start assembling.