Short answer: #3
IMHO I would not want anything except a Windows 64 mobile workstation, or even desktop, if I needed to make money doing SolidWorks.
Yes, its possible to run it on a MBP; I’ve seen it, seen consultant designers doing it, works for them, great. I think they struggle with large assemblies. I want a new MBP but would try and learn a different CAD package to run it natively on Mac.
Yes, I suppose its possible to run it on a Surface Book, but unsure if you can get a fast enough machine. It would feel like taking a BMW Z4 into the Baja 1000.
I am using (at work) the HP Zbook Studio X360 which has a Wacom screen built-in, and can fold backwards like a tablet. Despite this I use my iPP for sketching more often. The tablet functionality of what is supposed to be primarily a desktop machine is … funky at best. It doesn’t behave like a tablet should.
My team is using the HP ZBook Studio G4, Intel i7 at 2.7 GHz (I think its a 4-core, not sure), 16GB of RAM, and I think the Quadro 1000 graphics card. They like the performance for SolidWorks. I think it will be the best bang for the buck if SW performance is your main priority. Plus these new HPs are pretty nice looking and quite thin.
I’ve never thought about using the iPP as an external monitor.
Here are your basic hardware requirements: