Originally posted by Adam The k-5 ii uses the exact same internal hardware as the original k5, with the exception of the af module. So yes, the video stabilization is mechanical.
If you want the best possible video stabilization I'd look for a Sigma OS lens like the 70-200mm, as this would solve the issue that the k-3 has. Note that OS lenses were only produced for a brief period of time for Pentax, so some models (like the 17-50) may be very difficult to find.
Thank you for your response Adam, any idea if it is possible or likely for Pentax/Ricoh to enable mechanical SR in video mode on the K3 with future firmware updates? (considering all of the unimpressed responses by users on the implementation of electronic SR on the k3).