Cool Nate!
Yes, there are many options. The simple $399 box does a pretty amazing no frills job though. I have had zero want to have extra options and switches, but I also have enough outboard with serious headroom to not have to worry about it. It really only requires about 5 db extra gain, and this is actually just the nature of running MS. When combining 2 stereo sums, you simply must lose some volume somewhere, usually in the DAW you have to turn the faders down 6 to 10 db.
Here is a new video of our beloved designer messing with L+R and L-R..
http://home.comcast.net/~wqam/monster.wmv