Best Haswell Machine with a Digitizer

Been on the hunt for a convertible machine for the last few weeks, but I keep hitting a wall. I desperately want a machine on which I can be productive (use Office, code, etc.) but also can take notes that aren't always best captured in words. For these reasons I've started to look for a machine with a digitizer that is portable.

I have a workhorse of a desktop at home, but need something to take to class, presentations, and team meetings where I might need to do some things on the fly. My dream machine would be competently powerful (run at least 1 vm as required), last the better part (if not all) of a day, and have a good screen (i.e., >1080P).
Among the machines I've looked at are:
  • Lenovo ThinkPad Helix
  • Lenovo Yoga
  • Dell XPS 12
  • Sony Vaio Duo 13
  • Surface Pro
Each of these is a compromise in someway. Ideally, I'd get either a Yoga or XPS 12 with Haswell and a digitizer for use in tablet mode. However, for whatever reason, Lenovo and Dell think this not a sell-able (or maybe buildable) machine.
Any suggestions given these requirements? Let's assume for now that budget isn't an issue.