I make no claim to be an artist, but I have worn a cloak before. Anything with angles will look like you're pitching a tent, so I opted to round everything (more like a beetle). A lot of historical armor was inspired by insects, probably because the great exoskeletons they have. I did this the old fashion way - pen and paper....it's a concept at best.
The Helmet: (I wanted to curve the back of the helmet back towards the top of the head. You didn't specify what the back looked like...but I erased my creativity and kept it more towards your specs.)
[attachment=7245:SketchHelmet.jpg]
The Shoulders: (Keeping with the rounded theme - I thought it would be best to connect parts (sort of like an undercarriage) and keep the shoulders in several pieces. Also, I removed the single band and opted to have two smaller band that go between the underarm and chest to wrap around the arm.)
[attachment=7246:SketchShoulders.jpg]
The Chest Plate: (Those are supposed to be curved vents on the midsection of the chestplate....again, I'm not an artist.)
[attachment=7247:SketchChestPlate.jpg]
The Back Plate: (Those cylinder shaped thingies are the jets. I had them higher, but it looked Flash Gordon terrible....they're not so bad lower).
[attachment=7248:SketchBackPlateJet.jpg]
Twisted_Neather, I think this is a really cool idea. Had fun thinking about this. Good luck everyone.