Dahon Curl i8 - has 8 speeds, I know that is more than 6 but it is better to have more than not enough.

https://usa.dahon.com/bikes/curl-i8-2/

Depending on your price point - anything is possible. I just came across the following bike from a thread several years back here on BF. It is a 20" wheel bike with a TON of gears and breaks down pretty darn small. As the disclaimer alludes to - it is a pretty complicated build. Look at the pictures of it collapsed, though, and you can see just how much ingenuity went in to it (and apparently there were lots of "learning" projects to dial in the details in other frames that didn't quite make the grade).

One note I will throw out there - if you simply just scan the pictures and don't read it - the bike doesn't simply "fold" like a lot of the commercial ones (like the Dahon you had). There is only one part that folds - the rear wheel along the chainstays. The rest of the small package of the bike is from components that come apart entirely, then re-attach to attachment points for stowage. I don't think that should be a deterrent to anyone that wants as compact of a package as possible - by having parts that break apart like that it actually should be seen as a huge benefit because you gain another world of what is possible. You aren't held back from the limitations of geometry that fixed hinges hold you to.

I presume you could adopt the same theory to a 16" wheel if you really wanted that specific wheel size. Then again, going full custom like this you could do all kinds of neat stuff.

https://drewdevereux.wordpress.com/2...portable-bike/