Supporting proper per-user installs of Python 2.7 or 3.4 would require a second MSI that is configured to not ask for administrative privileges. The code is in Tools/msi/msi.py if you want to look at it (it's not my code and I have no intention of touching it), but the bigger concern is you're asking python.org to host twice as many files.

I'm planning to discuss installers at PyCon in a few weeks with the other core developers, so there may be a change of approach after that. Currently, we view Continuum and Enthought as the equivalent of any of the Linux distributors - either you live within their walled gardens, or you brave the outside world yourself. Linux distributions have shown that it's not a fatal split in the community, though it can lead to some obscure issues when people don't understand how they got/get Python.