Today is my son's 7th birthday, and he still wets the bed at night. It is VERY frustrating. I can have him not have any drinks after 6:30 (after dinner) and he goes to bed around 9. He goes to the bathroom twice before he goes to bed. Once before he starts to get ready and once just before he climbs into bed. Even with all of this, he still wets the bed. He has a small bladder AND he is a sound sleeper. Between the two there is nothing we can really do other than have him wear pull-ups or a diaper or whatever. He's skinny so we can get by with a size 5 or 6 diaper, which is cheaper than the bedtime shorts for the older kids.
About once a week he'll wake up dry in the morning.
Our pediatrician is aware and assures us that he will grow out of it.