Which got me to thinking - how would 'tache bars work on the D7? A bit of Googling found that lo, Dahon made a special edition singlespeed based on the Boardwalk frame, namely the Hon Solo, with featured Nitto Moustache bars and reverse action levers.
As well as looking wonderful, you've got a forward position with about 2-3 inches extra reach plus a really comfy sit up and enjoy the world position on the bar ends. Sure it will affect the compact fold but I think it'll be worth it. So onto ebay I went in search of a pair of Nittos. Then it occured to me that I needed v-brake compatible levers (currently only Dia Compe and Tektro make these) plus a bar end shifter (the Nittos are road diameter and won't take MTB style controls).
Which led me to think of butterfly bars - problem is that these would place the controls way too close for comfort - then I thought of North Road bars, which are pretty similar to moustache, with maybe a tighter bend, but crucially will allow me to use my existing controls. So more Googling ahead.
The joy of North Road bars is that you can tape the bend sections ahead of the grips (like Riv do with their Albatross bars and you can use all the positions). So I'm looking forward to finding a decent set of bars and making the mod.
One slight problem. My particular Dahon was put together by a gorilla it seems, and every bolt on the damn thing is ultra tight. So I've rounded off the allen bolt that holds on the Gripshifter, so will have to Easy-Out it before I can make the swap. I mean, no-one needs their Gripshifter that secure. Hey ho....
Anyone out there who's done the same or similar mod - very keen to hear from you!