They're not real (yet), but here's an idea of what they might look like.
KTM has acknowledged the development of a 490 platform by its Indian partner, Bajaj Auto. By the numbers, it doesn't seem like that much of a change from the existing 390, but this is an all-new parallel-twin engine, not an upsized 390 single. The earliest we're likely to see a 490 of any type is 2022, which seems a long way away. One artist, SRK Designs, has given us two interpretations of what these future models might look like.
This rendering of a hypothetical 490 Duke is not a radical departure from the current 390 Duke, despite the completely different drivetrain. It does borrow some design cues from some larger KTM models, though. For example, the subframe looks like the one on the 790 Duke. While the 390's taillight and rear fender stick way out behind the seat, this rendering looks neater, using what appears to be the parts from an 890 Duke R. The headlight is unique to the 490 but, like the taillight, resembles the one on the 890 Duke R. The family resemblance to a higher-end model is appealing.
As for the Adventure variant, the biggest visual change is better integration of the front end into the rest of the bike. While the 390 Adventure's fairing sticks out there in the middle of nowhere, it's tied directly into the body of this hypothetical 490 Adventure, much like KTM's bigger Adventure bikes. The 390 looks more racey, while this 490 looks a bit more grown-up, which it will be with its new engine. Again, the subframe comes from the 790.
Both renderings reuse the 390's exhaust. We should consider this a temporary stand-in since a parallel-twin will require an entirely different exhaust system. We will have to wait and see what Bajaj Auto comes up with, but these renderings seem like a sensible evolution of the existing designs while adding something fresh. KTM will be unveiling a new model on January 26, 2021. While the rumor mill says this may be the new 1290 Super Adventure, KTM could surprise us with a look at a 490 instead.