Will do regarding the mini-velo. This is my first complete build from the ground up (even the paint) and it's being spread out. Some of it is quite frustrating, such as needing an extra-long chain because of the 18.5" chainstays.

As for your folding bicycle, the biggest improvement you could make would be switching out the telescoping/QR handlepost to one that is a single piece with integrated, non-QR clamp. Finding one of these that's the correct height for you might take some time. An advantage of the Dahon is that aftermarket parts are quite available, even on Ebay. That's where I found the new handlepost for my Dahon.

To be sure the handlebar post is a major part of the problem with the bike. The flex is bad and the bars are higher than I like even when lowered all the way and farther back. I'd prefer drop bars, but they'd interfere with the nice compact fold that packs in a 62" case (mine does currently pack in a 62" samsonite oyster case).
Can you tell me more about the post you are recommending? Pictures? What does it take to fold for packing with the replacement post?

I have considered cutting the post off shorter and having the clamp welded onto remainder of the bottom section. I have not looked closely at how that might affect the fold.

The bike has been used as a loaner for friends and family members as much as anything else over the years, so I never got around to tailoring it to me.

http://img04.taobaocdn.com/imgextra/...!118407149.jpg
These handleposts don't adjust in height. They are each a single piece (other than the clamp at top and hinge at bottom), making them stiff. The four on the left have a 2-bolt clamp which you can clamp the handlebar directly to. When there's just this handlepost + a handlebar, the flex is minimized. You can find these handleposts in a variety of lengths. You have to be careful when searching through images of them, because the QR-version can appear similar from certain vantagepoints.

You can get right-fold and left-fold versions of these handleposts. You can also easily remove the handlepost completely, just like a threadless stem. I don't have any experience trying to pack a bicycle.

Here's how I can fold my bicycle with drop-bars, when it has no rear-rack to get in the way. Separate the seatpost from the frame before the fold. After the fold, put it back in with the seat pointing to the side. This is highly dependent on your personal setup, so, your milage may vary.
https://cimg6.ibsrv.net/gimg/bikefor...044fb971cb.jpg
https://cimg4.ibsrv.net/gimg/bikefor...dd5402a607.jpg

Thanks.