if i am not mistaken, variegation usually sports on plants, you would have to acquire cuttings from a variegated branch :\

I've seen quite a few seed companies selling seeds (at exorbitant prices)for variegated plants...could they be mistaken?

Interesting question. I Googled around a bit, and found this quote: "Seeds from variegated plants can "breed true" with variegated offspring, but they are just as likely to produce all green or albino seedlings [which are doomed to die]."

Most of the plants I have are variegated, they sometimes produce solid colored leaves, I remove them asap. I ordered some seeds on-line for Morning Glory Mini Bar Rose. It's not a "newly introduced" so I believe I should get variegated plants from the seeds. There's a "100% Satisfaction Guarantee"
so I can always get replacements or substitutions if I don't get the desired results.