Trufax. Well, I'm definitely with you on Spike and Sapphire. Most of the rest of hers are actually pretty common, except for Apus, but I'm not sure Twi would really feel right about doing anything like that with her without Celestia's express permission, and Aristo, who's too young. So maybe we should just stick with those two.

That leaves the question of how many of each type of egg. Are there rules about that? I can never remember.