Hi! Great that you want to implement support for more hardware! LinuxMCE is more than happy to accomodate, however due to the sheer flexibility and options on implementing this code, it can be a bit tough to figure out where to start.
What you want to do, is create a DCE device for your lighting interface. It involves:
1. Creating a device template, describing your device, what it needs to function, what commands it can receive, events it can send, and any plug and play information which can be used to find the interface.
2. You will need to implement the code for the lighting interface. Currently you can do this in either C++ or Ruby (or shell script, using the DCE Whisperer).
You should read the following wiki pages:http://wiki.linuxmce.org/index.php/GSDhttp://wiki.linuxmce.org/index.php/Developing_a_DCE_Device
And should you need more direction, feel free to stop by #linuxmce-devel on irc.freenode.net, and talk with developers. Hopefully we can get you on the right path.