So. I took the advice of a few gardening books and websites and just used one cool and one warm fluorescent tube in each of two light fixtures as "grow lights" for my seedlings. Even though they all assured me that this was Fine and A Good Approximation of Sunlight, I have to admit I wasn't entirely convinced. That is, until one of my cats discovered the lights.
She now spends a majority of her day basking in the glow of the fluorescent lights, even rolling around just like she does in the sunlight. I guess if it's good enough for a cat, it's good enough for the plants, hm?