One of the keys to dominating the developing markets is making Dual SIM phones and Nokia knows this, following the success of the very affordable Lumia 520, I'm surprised they haven't released a Dual SIM Windows Phone yet. But it looks like all that is about to change as @evleaks has released/leaked a screenshot of what is rumored to be the Lumia 630 aka MoneyPenny, a Dual SIM Lumia device.
As you can see from the screenshot, it can run 2 networks simultaneously.
And also noticed the on-screen hardware buttons: The Back button, the Windows button and the Search.
It is not confirmed if this is the screenshot for the Windows Phone 8.1
source: @evleaks (twitter)