This has already been mentioned but I think an online forum can only offer some general advice and perhaps which makes and models to consider or avoid. I know your location makes it difficult but there really is no substitute for test riding the bikes.
I tested about 15 different bikes, driving around 500 miles to six different ebike dealers, before I made a decision. And even then I agonised for days before I made my final decision. I could give you my opinion on each of those 15 bikes but it's all subjective. For instance another poster on this thread who owns a Cyclotricity Stealth 1000w has given it a good review. When I tested one, however, I thought it felt like a really cheap and unrefined contraption. I certainly wouldn't reccomend it as I think there are better bikes available for the same money or less. But that just shows that it's different strokes for different folks.
I also notice that many of your requirements are very similar to what mine were when I began looking at ebikes - mtb, lightweight, stealthy, price etc. as it turned out I was prepared to compromise on some of those things because other things e.g. power, hill climbing, build quality, and throttle - were more important. I was only able to discover that by testing a range bikes and then drawing up a shortlist. The thread I created, should you be interested, can be found here -
http://www.pedelecs.co.uk/forum/threads/mtb-or-hybrid-with-full-throttle-up-to-£1500-ish-for-short-commute.20296/
FWIW for a bike in your price range, to fit your requirements, I think the Kudos Tornado or Woosh Zeypher-B or Woosh Sport would be good choices. Or perhaps one of the Roodog bikes (Avatar, Striker, Explorer). Only thing to note on the Kudos bikes is that they don't have a full throttle. The Burisch looks like a really interesting proposition but I have not seen any reviews. If you get one I'd be really interested to read your views on it.