In theory such a thing is possible. In fact, I've even sketched out what I'd need to do to my one to convert it. I may still do it as a science project -- it's

In theory such a thing is possible. In fact, I've even sketched out what I'd need to do to my one to convert it. I may still do it as a science project -- it's an old unit (~2007), so if I destroy it it's not the end of the world. I can completely understand why no HVAC company would want to touch such a project. It's entirely experimental, would take a skilled technician, and has a high chance of not working perfectly. They would much rather slap together 2-3 installs in the time it would take to plan and assemble your science project. Remember that most of their techs are literally just installers, and there's a huge incentive to "rip out and replace" rather than "diagnose and repair". If you could find a retired HVAC tech, you might be able to convince them to help.