As for supporting a single product, I don't see the point of that. Using Nginx for load balancing will probably be much different than using Nginx as a web server, so the learning curve is similar.
Not that I don't welcome competition, I just don't see a real need in this space.
EDIT: btw, the Lua thing was an April Fool's joke...
EDIT 2: no it wasn't, my mistake. I was surprised by this so I checked the page and jumped a gun when I saw "April 1st" on http://www.haproxy.org/news.html. Sorry about that...