Hi D.,
Not sure if this will help you, but this is what I did with my girls, now 5 & 8. My oldest stayed in her crib very well, and really loved it. I wanted to move her out due to the new baby coming, and she was almost 3 yrs old anyway. Seemed the longer she was in the crib, the more attached to it she became, so the transition was hard. Here's what we did:
First of all we read lots of books about going to the big girl bed, and how exciting it was going to be. We set up her new youth sized bed in her room, right next to her crib. For the first few weeks we let her choose which bed she wanted to nap/sleep in. She started napping in the big bed, but wanted her crib at night time. I think she had both beds assembled in her room for a long time- maybe 4 - 6 weeks. ?? Finally I just said one day "You know Hailey, I think your room would feel so much bigger if you only had one bed. Why don't we take apart the crib and see how it feels in your room?"
That was it. No tears, no issues at all.
I guess in summary, we really took it slowly, and talked about it a lot. Another idea is to let her call someone she admires on the phone, and be able to tell that person she got a new bed, etc. (someone like Grandma, or even a hero - like Dora, Barney, Thomas, etc. Just have someone on the other end pretend to be the hero)
Good luck!
A.
PT working mom to 3 (4, 5, and 8)
P.S. someone else mentioned the crib tent. We used that too on my 2nd daughter because she tried to get out before she was 2. She wouldn't stay in the toddler bed at night, so I got too tired, and went with the tent. Worked Great! I still have it, if you're interested in it let me know. I've been meaning to put it up on Craigs list.