I have a Lenovo W530 that works quite well with Rhino - I don’t use T-Splines or Keyshot so I cant comment on those. It has an i7 -3740QM @2.7GHz and a Quadro k1000m-2048.0 MB graphics card.
I use it with a dock that connects it to two external monitors, mouse, 3dmouse etc. If you want to do this I strongly suggest steering clear of the usb docks. I struggled with one for a while before giving up and getting the full blown dock.
It got reasonable results in the holomark test scores here. Have a look in that thread, there are a lot of configurations that you can compare.
The consensus seems to be that you need a decent graphics card, ideally a workstation one (ie quadro, not GeForce) as Rhino uses OpenGL and not DriectX. There are plenty of threads on this topic if you have a look. Exactly what you should get depends on your budget.