If you purchase a DSLR you are able to emulate the features of the Lytro camera to an extent by following this guide: Camera Hack: DOF-Changeable Photos with a DSLRCamera Hack: DOF-Changeable Photos with a DSLR :
The gist is that we created a similar effect using a basic digital SLR camera and shooting video (getting depth-of-field information by capturing it over time instead of over space as Lytro does)
The main downside of this is that the camera will not be able to take moving shots.
Hope that helps!