Hello FrozenMan! Welcome to our All Spain Message Board!

Jo-Anne gives some good suggestions above. I know that Hostal Chelo has (at least) one average room with 4 single beds. Hostal López has a LARGE room with three (or 4 beds). Hostal Dulcinea has a kind of apartment which might be perfect for your family. Huespedes Jaén has well-priced apartments. And the El Prado apartment in Huertas (neighborhood) is cheap, nice, but smallish. Could sleep 4, I think.

Good luck and have fun in Spain! Saludos, MadridMan