Other manufacturers also make similar flat top "wing" bars as the K-Wing in both carbon and aluminum. Note that the flat top bars are in general 50-100 grams heavier than comparable quality 'standard' round top bars and many are not designed for clip-ons.
A few of the similar designs to the K-Wings.
Carbon:
Deda Electra
Deda Spectrum
Stella Azzurra Tirreno
Cinelli Ram Bar
ITM K-Sword
ITM Uniko
ITM Millenium Carbon Wing
USE Electron
Easton EC70 Wing
Modol Curvissima
Ritchey WCS Streem Carbon
Profile Dromo Pro Carbon
Aluminum:
FSA Wing Pro
Deda Glare Wing
ITM Lite Luxe Wing Bar
Cinelli Graphis
Easton EA70 Wing
Profile Dromo
These are just some of the models from the bigger, well known brands, there are many others on the market as well. Some are better designed and built than others.