Iverider
Cruisin' on my Bluebird
I think you would have a market IF you could lighten the damn things up and offer something for the 6'+ crowd. Build a cool looking streamlined bicycle that comes in at 20 pounds instead of 45 and you'd sell a few. Of course you have to build yourself one first to get the ball rolling. Maybe a few hipsters would want them as well. There's a custom frame builder that did a Motobike style 29er MTB frame a little while back. Retrotec does a cantilever style MTB frame that doesn't look quite proportionate in my opinion, but people buy those (and they're NOT cheap) The major shortcomings of these modern builders are they're missing the proper proportion and line in order to achieve a particular geometry (in most cases, MTB geometry)