I did consider mini split and there are a few reasons why I don't want to go that route. First is that I'd need at least 5 heads to get the whole place covered and that would not include bathrooms, where I do want vents. That means at least 2 units and they're more expensive up front, although the self install aspect can help with that. My biggest objection to them though, is the fan noise. That's one of the things I hate about the window units and while the mini split does eliminate the compressor noise in the room, the head unit still gives the fan noise and takes up wall space. I want quiet and not taking up space on the walls anymore, our vertical space is really at a premium.
I've run the numbers and will probably only go with a 16 SEER central air, above that and the payback period gets so long for the increased initial cost as to not be worth it. The only thing "special" that we're going to do is zone the master so my wife can turn it down to 64 at night without having to cool the whole house to that level.
I can get a 3.5 ton 16 SEER split heatpump with 100kw heat strip for about $2400, plus another $800-$1000 for installation. Duct work and startup is outside my skill set.