Scott,
The "Keyboard Porter" is NOT a heavy case, and having the wheels and handle are a blessing for the nursing home circuit, where I only take the kb and no sound system. Open the car - slide out the kb - pull out the handle - and "off I go" !
The model was the mid-size one, I think. There is deifiatly one larger, and I THINK one smaller too. Mine is a nice, tight squeeze with a bout 4-6 inches at the side for pedals, mic, cables and power adapter.
It's in the car, so I have no idea of what the model number is, but the "#7" rings a bell. See if there is a model that is the right size with a "7" in it.