I have no idea what the commercial lids look like.
We always have to make our own.
But let's see now.. What kind of lamp do you have? I used a hanging lamp (homemade; lightbulb, cord, flower pot) when I still had a glass terrarium with a mesh lid. I had it hanging from a strip of wood resting on the top of the lid, with a loop of wire going through the mesh. It's a bit hard to explain.
In such a small tank, I'd rather have it shine through the glass and not directly from above. Unless the mesh is metal.