I've gotten Blue Fire and Sandstorm on the first attempts, but still can't manage to get Sun, Moon or Rainbow. I did splurge for the "epic breeding cave," so we'll see if that changes....
For those of you who have succeeded in the 48hr dragons: what have you found works best--not just in terms of success rate, but also in how long you have to wait if it doesn't work? I've been trying crystal and blue fire but it's a pain in the ass to have to wait a full 24hrs when you just get a crystal egg back.
I can confirm cold + swamp for reindeer, too--got mine on the first try!