My KHS F20-Westwood didn't come with a carrying bag and getting one wasn't a high priority until I discovered the bike racks are removed from busses from November to April here.
A Downtube owner posted a link to photos of their bag: http://www.downtube.com/images/Bikes_7-14/BikeinBag.jpg and I put in an order with Downtube.
A BIG thank you to Dr. Yan Lyansky ("downtube" on this forum) for not only offering the bag but for the impressive 3-day turn-around, US to Canada. Yan can correct me if I'm wrong but I believe these bags are included with every Downtube bike - a great value-add when shopping for a folder.
I've attached some photos of the bag with the KHS - more to follow. (BTW: I'm using the stock, non-folding pedals and they fit in the bag)
The bag folds to a very neat, small package and appears to be very strong with heavy reinforced stitching. The carrying strap is padded and makes for easy carrying of the folded bike. In it's folded form, the bag has buckles to attach to a handlebar or seat rails.
Highly recommended. +1!
Thanks for Bruce and Rafael, and anyone else I missed, for their input on this too.
EDIT: bang on Rafael - you spotted the bars right away and the bag exceeds all my expectations. I'm still amazed at how compact it is when folded. :)