I'm wondering about the strength of the "rhombus" shape of the Spin frame for loaded touring. If there was a diagonal somewhere in there, it would be stronger.

I'm trying to find an alternative to a fold in the middle of the main beam because of past experience, to avoid irreparable damage. I also want something that can fit inside standard suitcases after disassembly, without having to pay oversize fees for checking into an airplane.

Splithub posted a photo on another forum where he completely disassembled his Spin 2, fork/handlebar, and both main beams out. It looks very simple with light tools that you would normally have on hand.
http://www.faltradforum.de/download/file.php?id=1762

On the other hand, Dahon and Tern hinge pins usually cannot be removed, especially if the pin gets slightly bent because it would be stuck inside. So the size of the folded frame becomes oversize luggage. Whereas a disassembled Spin 3 only needs a 24" x 16" luggage ( 61 x 41 cm). A hardcase (medium) of this size is easily purchased on Amazon cheaply. While a Spin 5 needs 25" x 20" (64 x 51 cm) and needs a "large" luggage. 51cm though usually can only be purchased as 75-80cm long (29-31") and reaches the borderline max check in size, but still do-able.

I was looking around and saw a few posts about Giatex.
Giatex Pony 166




Because of the way it telescopes, it "folds" longer than either mid-hinge (dahon) or rotation (spin), but the Giatex is narrower because the wheels will be in parallel instead of overlapped, and anyway this usually isn't much of a problem in daily use. But what is interesting is that if you take out the safety screw at the back end of the beam, it looks easy to pull apart the 2 parts of the bike for packing into a suitcase. I can't tell how the fork and stem been attached, and they may be difficult to remove. If they're left attached on the main beam, it would need an 80cm ( 31") long luggage. If it's easily removed, then it would need a 70cm long luggage since the beam is longer compared to the Spin.

Other problems:

• The seat/crank appears to be 5-10cm (2-4in) closer to the rear wheel than on Dahon's (heel strike on panniers, tipping backwards)
• How did they solve the offset seat post alignment (is the rear wheel at an angle by a few degrees from the main beam?)
• Finding a compact rear rack that can slip over the main beam when collapsing the bike
• No eyelets for rear rack upper stays, need a custom bracket to attach to where the fenders go
• No eyelets on top of the main beam
• The 2nd rear tightening knob might make more sense being on top than under the beam because of the rotational stress of the parts