Greetings. I've been a mapper / modder for years now; I started with DukeNukem 3D. Mostly UT2003-UT2004, but within the last year picking up HL2 and beginning to mod it. So far I have not released my own mod with Source since most of that work has been for various academic/research reasons. Currently I'm working on the Hi-Fives project.
The essence of the Hi-Fives project is to implement a scripting engine in HL2, and wrap a GUI system around that scripting system like, A.L.I.C.E. The hope is that the project will allow people without a programming background, artists, level designers...etc the ability to create a game. Our starting target audience will be High School students and teachers to use it in an introduction to programming class. Most of my work has been with regard to combining Source and Lua. Currently we are focusing on implementing the GUI, but the scripting SDK I put together has become very powerful.
In the future, my hope is to release just the Lua scripting module as sort of an open add-on to the Source SDK. This will allow for much faster modding to occur. Of course this is a huge undertaking, and may never happen. In the mean time, I may add some articles on implementing parts of Lua in Source. The kinds of things a game programmer might want to add to their game. The problem of course is that Lua isn't really a subject of Source, and so I've been debating if it has a place here.
One thing I've really been considering is wrapping VGUI with Lua. Currently the VGUI system is anything but friendly, to be perfectly honest. To be able to script the UIs in Source would be really fantastic IMO. Of course there are much more important things.
Finally, I hope to get a job in the game industry as soon as my collegic serfdom has ended :)