You can get a glass top very cheap and just get a replacement LED
strip or a T8 or a clip-on shop light or any number of things based on your budget and ability/interest in DIY.
If you can't find a glass top of the exact dimensions you need, buy one that is slightly large and get a cheap glass cutter at any hardware store. I was skeptical that this weird stick of metal was going to cut glass at first, but it works well and is easy. I used old picture frame glass to cut down glass lids for my oddly sized 33g long tank.