Would I still be interested in one if 16/20 ga. is what's ultimately offered, yes. Would I prefer a light 12, also yes. I know there are some strong 16 ga. proponents but for anyone planning on resale ever I'd think 20 or 12 would be better bets. Really, I'd think it would make the amount of initial order higher too - I know this won't be a high production gun but I can't see single digits being economically feasable.
I'd really think going to 26" barrels would be a bad idea - if only one length will be ordered I'd suggest 28", and if two 28" and 30".

I have no idea on how any this would move the cost and availability of barrels.