I just released an Openframeworks Addon to work with Kuler service namely ofxKuler. You will find all theme related services are implemented.
Please let me know if you have any suggestion or a bug report.
By this i also want to report some inconsistencies in Kuler API. Especially in search API; when i tried to request by user or theme id's some times i received randomly filled results. Hopefully im wrong about it, since i couldn't tested further to spot these issues to make a useful report, but just to let you know my experience. Some times its was also very slow in my fast network.
Anyway, thank you for this service and hope you find this addon useful.