Does the rice cooker need a special kind of lid with a vent or will any suitable-sized glass lid do? I often find thrift stores have a wide selection of orphaned Pyrex-type lids, if one of those might work...they might even have orphan rice cooker/pan lids.

Otherwise, how much would it cost to just get a new large rice cooker? Is it really worth hanging onto both the small one and the one you can't use until you find the right lid?