Joined: Aug 2010
Posts: 12,726
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I think that some Bike Fridays have replaceable dropouts for different types of gearing systems (derailleur versus Rohloff, etc.). I have not seen them but I think that I saw some photos of such on the internet. If so and if your frame builder can buy the Bike Friday dropouts you want initially and build the chain and seat stays for that setup, that gives you more options later.
But, if you are certain that you would not want those options later, skip it.