I was buying white grapefruits from Hale Groves, but their fulfillment is very slow. Not too many companies have white grapefruits--ruby reds are more popular. Do you like ruby red, and do you have a good, reliable source for them if you do?
Most people have only tasted fresh grapefruit, and not everyone enjoys the tartness of it. Jenny Stewart of CHOW.com suggests broiling the citrus fruit with sugar to add a caramelized sweetness. And if you're adventurous, go crazy with any flavor combination you can think of—you might be surprised how well it works.