I'm building a system to do decent quality remote webstreaming. There are various options (security cams, ip cams etc.) but at the moment the bottleneck seems to be a 3g/4g upload (Huspa - 800k/bits - 1200k/bits upstream UK) - therefore, as I can accept a 1-2 min time delay - my current view is the way to build this is to create good encoding platform which takes a firewire/usb3/hdmi-in->usb3 input from a video camera (need 16x9 -would like a system that can give 576p, 720p and possibly later 1080p). I have this in prototype - but am realising the webcam I am using Logitech 910 is not really good enough

currently usb3 cameras are too rare/pricy

So my question on this board is

If I want a decent priced 'camera' whose only purpose is to
a) provide a constant raw firewire/hdmi-out stream of a typical outdoor scene (e.g. landscape or possibly cityscape) at the above res
b) provide a nice crisp picture (crisp = better encoding)
c) have some ability to zoom (with autofocus, and possible manual over-ride) driven by a remote interface (usb?)
d) ideally low-ish maintenance (this thing may have to sit in a box for 6 months)
e) so I don't need storage, still images, self-portait,

price approx 150-350 - happy to build from parts

problems I am backing off for the moment are audio, and some motorized platform - any advice here is of interest

I have a little experience with cameras with videos (panasonic t7, canon ixusi200, samsung) from a previous project - but these dont seem to do live video out

thanks in advance