At EcoBuild at Earls Court I was talking to marketing men of boiler manufacturers. I mentioned this and why they don't make boilers with insulated water tight cases to be bolted on the outside. Rinnai are the only gas appliance maker to make an outside appliance. Many were enthused and were eager seeing a niche in the market.
A gave examples of new builds who would want a high flow combi and a jig to connect the pipes and then the boiler is fitted on the last day to stop the ****** stealing.
New builds would love it, as it frees the kitchen and airing cupboard and less pipe used. A yellow gas underground pipe to the back of the house to a boiler in a box there on the wall, a tee and into the kitchen for the hob. Maybe a secondary circulation kit like the Ethos. No noise, safe, easy to service, etc., saves masses of space and cheaper to fit. Their minds were racing. They said they talk about that back at the office. It's so obvious.