Gary's right about the Predator... it looks romantic but is not a stable platorm, esp for a beginner.
Read up on the different threads here and the FAQs as well.
Your idea about the multi-engined hovering is really out there, unless you want a quad-copter.
Also the thermal cam is pretty expensive and really an advanced item... start by getting in the air with the EZ and work from there.
P.S. I think you'l find that a hollow exterior has yet to be invented!
I agree with the above, the plane looks great, however it's not the best for slow speed flights and has some interesting characteristics at lower speeds!
I would recommend the Easystar or Skywalker, with the information you have given I would lean towards the Skywalker for size and the amount of additional weight it can carry. The great features of these two planes are you can repair nearly all damage at the field with a pot of glue and be back in the air in a few min's. The building is easy if you have built one before, and this might be the most important point, they stay up for a long time (my EZ* on a 2Ah battery will be up for 25 min's on a charge) and the APM works straight out with the code, no huge amount of tuning required!
I'm in the process of helping another member building a drone, this will be almost a RTF from the box, I will be going with one of the above airframes for ease of flight and great adaptability on top of the points I listed above.
I see you are from the UK, have you seen this?
Embrace your noobness and start simple. Anything RC related is better that way. If you have no RC experience, start with this plane:
If you do have RC experience, start with that plane anyway, and get an ArdupilotMega kit if you're comfortable with soldering electronics http://store.diydrones.com/ArduPilot_Mega_kit_p/kt-apm-01.htm
Or preassembled if you're not http://www.udrones.com/product_p/expck1.htm
As far as controlling it when you are no longer in range of your RC equipment, this is probably illegal in the UK. It is in the US and Canada. Flying a UAV requires licenses and permits to use. A hobby or amateur UAV is no more than a radio controlled plane with fancy electronics, and must be kept in visual range at all times.
As far as wanting a predator, I want one too! But.. the wings are just too narrow for any amount of stability. I'm sure it could work, and would look SO cool, it would require amounts of RC talent and patience to tune the ardupilot properly that is rare even in highly experienced folks. I plan to paint my Hawk Sky flat grey, and make sure it has sufficient external antennas so it will at least LOOK like a drone, and not a foam RC plane.
Hi Don you are correct on the UK, it's only LOS flights.
If you are looking for a kit pre-build there is one closer to home here, UK stock :