I've been using the plastic cat/small dog bowls from Target. This model is only a $1.19, and very smooth underneath--the 'finger holds' on the sides are just the right size to provide an opening for the babies to crawl underneath the bowl. These are both water bowls, and hides, in one. The babies seem to love them, and they save space in small bins.
http://ecx.images-amazon.com/images/...LL._AA260_.jpg
They will fit in the small boaphile hatchling bins, and in the Vision hatchling bins as well.