The eBay route was interesting, However, most of them are just extensions of similar budget heating and cooling websites that offer lesser efficiency systems at a reasonable cost. I lack the vacuum pump, guages, flaring tools, and license to handle freon, so unfortunately, DIY is out unless I can get someone to hook up the refrigerant lines and balance the system.
I'm getting a few quotes now. My preference is for a York or maybe Trane system. I have a quote for a Lennox system as well, but they tend to be proprietary which I see as a liability when it comes to parts and service.