In the Sticky for this forum (Lightest Carry-On Bag), I believe someone mentioned that the Lufthansa Store in FRA sells Travelite but it seemed like only a model or two.

Also, here is another post from that same thread about a place that will ship Travelite to the US:
http://www.flyertalk.com/forum/12182940-post54.html

If you are looking for a reasonable alternative that you can get in the US (for a carry-on) see this post:
http://www.flyertalk.com/forum/14509066-post164.html. I ended up getting the bag mentioned in the link. While I haven't traveled with it yet, it seems very nice. As a bonus it was also lighter than the Travelite that I had been thinking of getting.