Most people build their own cages because pre-made are more expensive, hard to find and often not exactly what the quail-keeper wants. You can remodel rabbit cages by wrapping them with half-inch hardware cloth. Try to get used ones... lots of used rabbit cages out there. Not apparently out here, alas, but we’re pretty sparsely populated.
“Rabbit Housing” by Bob Bennett gives very clear instructions for DIYers. Just use 1/2” hardware cloth and do everything else more or less the same. Stop by the quail hatchalong thread for lots of experienced quail keepers (I’m just a wannabe so far.)