That's a fascinating set up and quite an unusual "mouse" - it had me off on a web search to identify it. I like the way you've integrated the two.
It's a 3d connexion mouse. It's very nice for when your working a lot with 3d drawing software. There are also some that have more options, but not one has a integrated numpad.
And with an full keyboard i do not like the position of my hands, but with the TKL i have now i miss my numpad
)
So i came up with this idea.