@rowr: Thanks dude, not quite what I need.
Probably to do with the way I worded the question. What I need is to be able to choose how Windows boots at the boot menu (AKA: that thing that appears asking you to if you want to boot into safe mode when shit goes bad).
- The default option selected after 10 or so seconds, this option auto boots steam as a shell.
- Boots windows but allows me to select which account I log in with.
I know how to copy a boot config using bcdedit, but that is about it.