Crib tent... How about just using a tent instead of a crib? We did this successfully for both of our kids. You just get a small tent and a mattress that fits it. The first time we had to have a mattress custom-made, but the second time we got lucky and found one that fit perfectly.
Advantages: 1) The kid is in an environment that is a bit warmer than the room and is draft-free. 2) If s/he falls down, s/he doesn't get hurt. 3) S/he can be zipped in safely while allowed the freedom to roam inside. 4) Night lights and other light sources are diffused.
We got our first tent because our one-year-old daughter managed to climb out of her crib. Scared me witless. After that, no problem. Just kissed her goodnight and zipped her in.
"I have no known mental disorder ." -CCT