If Northrop Grumman has this airplane flying around right now, patents like these are our only clue that it exists. This particular drawing shows one of Northrop's "Next-Generation Bomber" patents, an evolution of the B-2 Spirit. The most notable new feature? Those little retractable mustache-canards. Adorable!
The Next-Gen Bomber (NGB) program was originally supposed to deliver a stealthy, subsonic, medium range, medium payload strike aircraft by 2018, but in 2009, it was cancelled in favor of a cheaper and more versatile "Long-Range Strike-B" (LRS-B) platform, which will be delivered sometime in the mid-2020s. This Northrop Grumman patent is for the NGB, not the LRS-B, but it's very likely that the two designs will be similar, and this is the best look we've got so far.
If there's something familiar about these pics, it's because the aircraft looks rather a lot like a certain other futuristic project that Northrop Grumman has been working on, the X-47B unmanned combat air vehicle:
Both the patent drawing, and the X-47B, feature the same "cranked kite" planform shape. The NGB would have been ten times the size, of course, and it's got four engines instead of one, and it's intended to be flown by people and not just robots, but you have to figure that Northrop has fixated on this overall design for a reason, primarily aerodynamic efficiency and stealth (or maybe the other way around). We're loving the addition of those little (not so little, really) canards on the NGB's nose: they'd be retractable, adding some extra control and lift on take-offs and landings.
It's also worth noting that the LRS-B isn't intended to be a heavy bomber, since the B-52 Stratofortress is somehow expected to remain in service in that role until 2040. The B-52 Stratofortress, for the record, entered service in 1955, so it's already ancient, and this new "2037 bomber" won't be taking over until, you guessed it, 2037. The designs we're looking at now, then, are intended to fill the gap until this new 2037 bomber hits the skies, but it'll probably be a while before we get any official word on the project from the USAF.