We know one more feature of Lumia 730 now, if the above leaked image has to be taken into account. It looks part of official press renders and may confirm both Lumia 730 name and the fact that it will have a Dual-Sim variant as well.
Here, we reproduce probable ( they may change ) Lumia 730 and Lumia 830 (name yet to be confirmed) specs for you again,
Lumia 830 | vs | Lumia 730
1) Display: 5-inch | vs | 4.7 inch with similar 720p resolution
2) Design: Metal Frame with polycarbonate back | vs | Polycarbonate Unibody
3) Processor: Quad-core Snapdragon 400 | vs | Quad-core Snapdragon 400
4) Rear Camera: 13 MP PureView camera | vs | 6.7 MP camera with Carl-Zeiss optics
5) FFC: 2 MP | vs | 5 MP
6) UI Navigation: Hardware touch buttons | vs | Hidable On-screen touch buttons
8) Camera Button | vs | No Camera Button
9) Both will run Windows Phone 8.1 update 1 out of box
Thanks NokiBar for the tip. Cheers!!