Dragon eggs?

It seems to me they were far easier to get before. I've been to the lairs dozens of times in the last two weeks or so, and only once did I find an egg - which happened to be a difrent color than I wanted. How come that, with both search and spot in the vicinity of 20 points, I can't find something so huge? What influences the chance to find it?

I am not sure.  My own sorceress recently went and got her blue dragon egg, her search skill a bit lower than your 20, spot about the same, got the egg no problem.  I am not sure how difficult the copper is supposed to be to find.

You're not precluded from finding the other color, btw.  The limit is just that you can only successfully hatch one of the two eggs.  Keep trying for the other one.  I got a cloak of vision I could lend you as well to boost your search up +20.

I have it too, actually, just forgot it gives that bonus. Will try some more.
Edit: Tried it, didn't work. Then decided I'd go all out and craft myself up to the +50 limit. Still nothing. Checked both caves to be sure, multiple times.

I think I need to relevel to get enough base skills, epic focuses and INT+WIS to find it. It's not like it's a huge thing sitting right in front of me or anything.  

It shouldn't be that difficult to find.  My non-ascended sorc found her dragon egg with 24 search, I think 30 some odd spot (cloak of vision plus decent wis score).

Might be something off in the search trigger itself.  Multiple tries with sufficient skill should have gotten something by now I would think.

I think so. I remember going there when the dragon thing was new and found it on the first, maybe second try with much, much lower relevant skills.

I found both the copper eggs and the blue eggs at low levels, such that I didn't think it was anything but a plain trigger with a random roll of possibility, not a search or spot check.

Was it recently?

No, finding them at low levels was quite a while back, although I went there a few months ago with my L40 Wizard who had only minimally adequate Search and Spot and it seemed unchanged in behavior.