Why do you need such fine granularity in your pricing? If I were in your place, with some 200 realistic combinations, I would put them into 20 different buckets, in one of two ways:
1. Any print up to 8x10" costs $xxx; up to 11x14" costs $yyy, etc., or else
2. Any print up to 80 square inches costs $xxx; up to 160 square inches costs $yyy; etc.
In case 2 you can include a simple calculator on your site to compute square inches (or cm, or whatever unit you want).
Then you have a small, finite number of different prices, which you should be able to plug into any cart system easilty.