Here is a thought: How about an entry level tubed integrated (JoLida, nOrh, or others?) for less than $580 new paired with a used set of monitors or mini-monitors (e.g., Omega, Triangle Titus, B&W LM1, etc...). You would also need a few bucks for speaker stands and then find some lower-cost wires as suggested above. I have been thinking of adding a system such as this as a second inconspicuous listening post in a formal LR of about the same dimensions you list. I don't know if it will work or not, but that is what I have been researching.