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.
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"I have no known mental disorder ." -CCT