I'm assuming it took many trained, experienced, professionals working an absolute minimum of 8 hours a day a couple of years to write the Unreal engine (again, an assumption). I'm not sure how much experience you have, but I don't think you're going to have too much luck witting an engine similar in quality to the Unreal engine.
Though, if by "similar to Unreal", you were merely giving an example of another engine of unrelated magnitude, then you would have luck with that (again, depending on your experience level, but definitely more possible).
However, the only development tool for the 360 that is available to the public is XNA, and I'm unsure as to how well you could write an engine with XNA. And I don't think there are any development kits for the PS3 available to the public. But for the PC you can use DirectX or OpenGL.
yeah, i was going to *ahem* borrow........ the source code from XNA, And I know people inside Sony.