LD and Brightstar Productions are the two I have dealt with in my time in Houston, as well as some smaller companies, but none of them would have enough to keep you busy.
I hear Brightstar might be expanding their sales side of things, but I am not sure about their production and Live sound departments.
We pulled in LD last year for a major event and were quite happy with everything they did. I was tied up in my venue, so I didn't get much of a chance to see what all they did on campus, but dealing with the company was easy and they certainly handled everything professionally.
I grew up in Cleveland Oh and moved here 3.5 years ago. I miss the seasons, but not having to worry about driving in snow is something I don't miss. Just get ready for the summer that doesn't quit!
Jon