With some popular flat SA keyset being made (JukeBox, 1976) has planck kit with legend I think SP already has the molds so the pricing is no problem (Godspeed Planck kit only $25ish). And please don't take pricing too much into consideration, we all know this is expensive hobby, nothing you can do to make this cheaper if you want custom things with quality. And more people means more price drop and as I already said, this is Lego themed we are talking about, the market is already there, you just need the right platform and I believe this will hit 4k buyer if not more.