A bunch of new camcorders were introduced at the Consumer Electronics Show. New hard drive and digital camcorders with proprietary codecs that you won't be able to edit in your NLE. See http://www.camcorderinfo.com/
The Panasonic GS300 is apparently discontinued and replaced by a model that doesn't have external microphone input.
Treat your Optura 50's and GS 400's with care -- they were apparently the last of their breed: cheap 'corders with manual controls and inputs.