I've pondered coal fired clothes drying, getting real hot air from 180 degree boiler water causes longer drying times from what I can tell.http://outdoorwoodfurnaceparts.com/products.php?cat=18
If that unit works, maybe a stock electric dryer could be modified but I think the real solution may be in Europe, and that is painfull to say.http://www.prweb.com/releases/2008/04/prweb866454.htm
A clothes drying cabinet, less air to heat, and not quite as warm, with longer drying times. Support from the better half would be required.http://www.askousa.com/laundry/drying_c ... et-dc7583/
These are electric but might be a start, the temperatures are lower so hot water might do it, and they should be darn near silent, just a fan.
And no lint just like line drying, vent inside the house without lint concerns.
Just a starting point, for sure, cost seams high. I'm not sure how to build a wood cabinet that would handle the high humidity but maybe start with a fiberglass shower and add some stainless racks, it just gets messy. Maybe wood cabinet with hull paint, I just don't like wood for this.