this is what we did last spring. our daughter was very attached to her binky, although we only allowed it when she was in bed (naps/night). We never thought we'd be able to get rid of it, but took some advice from friends and came up with a plan. when she was 25 months, we switched her over from her crib to a twin bed. she was so excited to be a big girl, and to have new big girl bedding with butterflies. she was so fired up, it was cute. several people I talked to recommended getting rid of the binky together with the bed transition, but we were scared to the first night. the night went so well in her new bed, that the next day I just decided to go ahead and try.
she and I had a long talk about it, how she was a big girl now and had a big girl bed and how big girls don't need binkys, that binkys were for babies. we talked about my friend's new baby. even though my friend lives in florida, my daughter was really excited every time we got a new picture. anyway, I asked her if she wanted to send her binkys to baby delaney. she said yes, so we called baby delaney's mom and asked if delaney would like them. thankfully my friend played it up and katie was excited. we were already putting a box of baby clothes together for her, so we put the binkies in as well (I did take them out when my daughter wasn't looking).
The first nap was a bit rough, she asked for her binky and I reminded her how we sent them to baby delaney. she pouted a bit, but didn't cry, and went to sleep. shocker. same thing that night. In fact, for the next few weeks she asked for her binky and then we would talk about baby delaney and how nice it was to be a big girl and have a big girl bed, etc. She had a rough patch about 3 nights in and was crying for a bit...this lasted a couple of days and I almost caved, but then suddenly she was fine. she would still ask at bedtime/naptime, but would start to giggle about baby delaney having them.
sorry this is so long. just want you to know it can be done, and good luck!
eta, a few months later an online friend did the same thing, but she had the baby they sent to binky to send a thank you present that a big girl might like. I love that idea.