Have you ever been to the campsite, seen a tent, gone inside and saw a dreamie? Well, yes, probably. But have you ever had a dreamie with 10 villagers? I absolutely HATE it when that happens!
Yeah, I used to not check my campsite when I was still on the lookout for Sydney but already had 10 villagers. Then one time curiousity got the better of me, and I went in.. And thank goodness it was Yuka, but darn, those two look so much alike (especially from behind!) that my heart sank for a moment when I entered.
Definitely try the Villager Trading Plaza subforum when you have space for your dreamie again, I believe that's how most people here get their dreamies.