I agree, a t-shirt or 2 would be great!! You can also have an announcement card made - there are tons of arrival letters or cruise announcements on here. I have some I could customize, or check natalie or kellybells or any of the other DISigners - like I said there are tons.
I've actually made my son "arrival" baskets for our trips - loading them up with all the things he'll need while at Disney ( disney dollars, his own camera, autograph book, pen, spinners, pal mickey, swim suit, towel, flip flops, hat, sunglasses, pj's, journals (natalie has some awesome ones) kidcot passport, etc..... etc...) ( I got a lot of his stuff off ebay - but there are some people here who make arrival baskets ( I think) at least there used to be, one was feralpeg, but I think she works for disney florist now and not doing it anymore - but, do a search for arrival baskets and you'll find them if you don't want to make your own - plus they deliver to your resort, so if you are worried she'll see it or you are flying that may be the way to go!!! *** Actually, disney florist does them too.......
www.disneyflorist.com
Here is a link to another DISigner here on this board who makes short intro videos...........Watch the video first - then, if you like it, you could request that maybe they put her name and that she is going to disney with you - I don't know if they can, but it's worth a shot.
http://www.disboards.com/showthread.php?t=1757953&page=36 - just click back from the last page till you find a video link and watch it, - they are all the same, except the names are different since they are customized.... anyway, make sure your volume is on so you can hear it!!
I'd just request on that thread what you want -- maybe they can do it!!
Then you could play the done video for her and let her open her arrival basket. OR if you want to hold off on the arrival basket until you get to disney that would be good.
Here's a quick story of what we did once, I made my DS an arrival basket and wrapped it up in celophane (just like easter!!) when we arrived at the lodge - DS and I went in with the bellhop - DH had another bellhop take the basket to the check-in desk and tell them who it was for........ DS never saw it. When it was our turn to check-in the girl went into the back and brought out the basket and gave it to DS as an arrival gift from Mickey & Minnie - he was so excited and everyone was so into it and excited - It was just one of those moments that touches your heart!!! It was great!!! Anyway, that's another idea you might try.
One stay my sister checked in to her resort and that night when her DD went to sleep she sprinkled pixie dust all around the room with a note from Tink........... to follow the pixie dust to find a treasure........... it was her arrival basket. She actually even made little footprints with powder that she added sparkles too......... it was toooooooo cute!!!!!
Anyway, I'm sure you'll get lots of ideas here .......... and do check the threads, I'm sure you'll find some cute shirt ideas.
( I can customize some for the 3 of you to wear while on your trip if you want!!! - Look through my thread or if you have an idea - let me know!!)
Good Luck
. (We are actually taking her. She's going to be 8) 
. We thought that the DVD which Disney provided would be what we would "wrap". Now we see that it is totally irrelevant (although good for planning). We'd like to find a slide show or something similar which we can give to her on her birthday. Our creative abilities are zilch!!
) are fabulous and so generous, donating their time and talents to fellow Disney-lovers. I'm certain one would be willing to help you out.
