What I use is a locally milled game bird... starter I think. I seem to have ripped the tag off to put it some where safe and forgotten where that safe place was... Anyway, it is 28% protein and I had to go out to my home town, a farming community, to get it but they did have it regularly stocked.
Purina Game Bird Startena is 30% and tends to be the easiest thing to find, however the image above is the bag that all of their game bird chows come in, you will have to read the tags to see if it is maintenance, flight conditioner, or startena. If you're lucky they stack them separately but some places with lower demand will just pile all varieties together and you have to check the whole stack.
Turkey starter would be the highest protein turkey food and would be the one likely to be high enough for quail. If you've seen game bird flight conditioner or maintenance food at feed stores in your area, especially the Purina brand ones, then they can order starter for you. Depending how high volume they are it may take a long time to come in and you will have to make do with something else for a while. In my area I found small bags of
Manna Pro Show and Game Bird food, I believe that was 24%, and I made due with that until I could get to the other feed store outside the city.
Outside of meal worms and egg you can get BSF at some pet store or attract the native population to a colony of your own design, you can find discussions about that here in both the quail and chicken forums. I have also heard of success with using commercial fish food, like the sort for catfish farming, mixed with lower protein chicken food. If I recall correctly if you're using equal parts of different items to mix a diet you add up the protein content of each and then divide the sum by the number of items mixed. For example if you mixed five pounds of 20% protein chick starter and five pounds of 32% protein game fish chow the resulting feed would be 26% protein, which would be perfectly suitable.
Cheers,
Jessie