#1: there's no 8 speed igh Dahon bike that folds this way,...
#2: cromo steel, it's what the Uno is,...
#3: my speed p8 has a derailleur, and I want a straight chainline,...
#4: the Uno is shadow,... :P
#5: I luv the bike,...

Modifying bikes is fun and he has the Hub ready for action it sounds.
To your point however, I personally really like the Vitesse D3 which is effectively a Speed Uno w/ an aloy frame and Sram/Sachs 3 speed.

For "ultimate" Internal setup, I just modified a bike and I really like it. No pics it seems so maybe I will post tomorrow.

I suspect the belts are not that heavy but the chainring and sprocket are unless you get into exotic metal manufacturing choices. I am surprised it is that much different. Roger

My prior is that with respect to a chain, chainring, and cog, the belt drive would be lighter not heavier. I thought that was the case with tandems and timing belts, for instance.

Dahon Speed Uno Folding Bike
 

I still have it,...and I luv it.

I am always baffled by people wanting a One speed. To me one of the joys of bicycles over walking is the efficiency of being able to gear down for hills and up for flats. I also don't understand the facination people seem to have with belt drive. Chain drive is so easy to work and fix. A pant strap cures most of the pant leg issues.

Chain Drive Rick

the world of bicycling is a wonderful diversity. i love having a single speed to ride around my neighborhood, and i love the freedom of a no fuss no bother simple and clean bike. i have other bikes for multi speed uses. i have a fat bike and an ebike we all have different likes and opinions, chain drive rick has his.

I have read that the Speed Uno had an inferior frame than the Mu Uno. Is that true? I want the Mu Uno but I see that they dont make it anymore. Does this mean that the current produced Speed Uno is just as good the Mu Uno was?

The Speed Uno has a stronger chromoly steel frame. I don't see how it's supposed to be "inferior". The MU Uno was just marketed as being a more premium, lighter weight single speed folder. I chose the Speed Uno for strength,...it's never failed me.

Technically, no. The frame build should be of similar quality.

Variances will be the the material and the components.
The Mu Uno is Aluminum Alloy (Dalloy in Dahon parlance).
The Speed Uno is High Tensile Steel. Higher would be Chromoly. Perhaps Dahon upgraded to that in the recent build.

In terms of components: Mu generally has good high end components. Multi-Speed bikes normally have Skewered axles and higher level hubs, sealed bottom brackets and also double wall rims.
Some of these subjects are difficult to parse. Generally Dahon has single wall rims when they offer nutted axles (I would have to study how the Mu Uno was sold). I would prefer double wall rims and the choice of axles. Upgrading BB's are always easy and I do so often.

I have not seen (or taken apart) the latest Speed Uno. The price increased significantly. Perhaps that means that component went up, but it could be that no other market sells the bike so the price is based upon volume. I am not sure.

Mu Uno was always a very nice Bike. Came in a few variations. 20" - full build. 20" Belted. 20" 451 Belted (I think)... I always sold them rather than using them as we have hills, but I thought often about converting a Mu Uno to 3 speed.

Anyway, the Speed Uno is a nice bike and very practical for upkeep. (I liked the old Vitesse D3 which was like a Super Speed Uno).
At present it is the only single speed Dahon. You can get a Multi-Speed IHG Vitesse. Nice frame. Wheels are single rim and nutted axles, but that is the only real drawback to the bike.

Hope this is helpful.,

My Speed Uno is comoly, NOT high tensile steel. Unless Dahon has downgraded the steel used.

Update: yup, the new model is high tensile steel. I'd recommend looking for an older Speed Uno,...in Shadow,...cromoly steel.