Quoted from RobT:
I don't know why people keep referring to Heighway as a "boutique" pinball maker. Just because they haven't delivered a pin yet does not make them "boutique". They plan on selling as many of the pins that they make as possible, and as pointed out above, they have a big factory in which to build the machines.
Boutiques would be much smaller runs (a hundred or so) and built in small shops, not a factory.
Because around Pinside, boutique means anyone other than Stern. The current King of boutiques is JJP.