While it does not address your lock request, I found someone who is selling canvas zip up bags for very reasonable on Ebay that look like they would hold a Strida and ordered several. Fold, zip, take with. For me, I would never leave my Strida unattended outside. One issue that has not been addressed is that it does not appear to take much force to seriously damage the bike, for example clipping the belt, and there are those who if they can’t steal something might show their displeasure by harming it.