Chris - First of all, let me say welcome to Vacuumland. Nice to see a new poster with a very novel idea!
It's also nice to see that although you aren't a vacuum collector, you have respect for & understand why we do collect them. I personally got into vacuum collecting because my Mom was a professional housekeeper & was fixing her vacuums for her all the time, & 1 reason in particular was I was sick & tired of seeing all the cheaply made, poor quality garbage on the market that doesn't last & more importantly, doesn't even clean well! Not only was I interested in collecting them, but studying the different designs to find which designs actually work well.
However, I agree with some of the other posters here that, for your uses in a single family home, installing a truck mount extractor might be a bit overkill & could possibly be dangerous.
There is an alternative product, though, that I'm sure you hadn't considered. How about using a central vac wet/dry interceptor? Aqua Air makes one, & what it essentially is is a bucket with a hose on top to hook up to the central vac, & you hook up a long wet/dry hose to the front. It uses the suction & airflow from the central vac to pick up & separate the water, so you could use it for carpet extraction cleaning or floor cleaning like what you want to do with the truck mount installed in your house. You would use a faucet connector or have a connection installed on the water pipes under the sink to supply hot water.
The best part about going with the wet/dry interceptor is you can use it now, not wait until your new house gets built, it makes the best use of the central vac investment you already have, & no having to deal with electrical connections. When you build your new house, you could also justify using the wet/dry interceptor for getting a much more powerful central vac unit than your house would normally require, so when you do use the interceptor for carpet extraction cleaning it performs the best you can get out of it. If you dislike the thought of lugging up the interceptor & the equipment up a flight of stairs, you could always keep a set on each floor.
I also would consider going with a water filtration central vac system like Drainvac or Aqua Air when you build your house. Yes, I understand your concerns you expressed above about sludge buildup in the pipes & possible leaks. But I'm willing to bet that these systems don't use the standard central vac pipes - they likely use something that resists these problems - and also the installer the central vac dealer will refer you to will ensure these problems DO NOT happen after the central vac system is installed. I think the fact these systems have been around with these companies for decades now should say something about their quality, safety & effectiveness.
Best of luck in finding a solution that works for you & does what you need it to do.
Rob
https://aquaair-wetdry.com/category/power-units/dry-wetdry-interceptors/
