I remember @Mrs. Bee posting about this, and @Chopsuey119 also talking about a floor bed..

I have a question. I am considering doing this for my three month old son, who will only sleep on our bed. At first I thought it was smell-related. So I slept with his blankets/sheets but he still wouldn't sleep in the cosleeper next to our bed. I think that the reason is our mattress is much softer than his very firm/hard cosleeper mattress. I wouldn't want to sleep on it either! So we've been considering getting a twin mattress and putting it on our floor to start with, then when he weans from night feedings, put it in his room.

Who has had positive experiences with this? And what did you do when they started to crawl?