I know what you mean, like Audi or Volkswagen oil filters but made by Mann who produce the actual parts, or Textar for BMW.
That said - I'd pay the money for genuine OE. Given the time and effort to drop the leg, do a gear oil change and possible water-pump gasket change, do you really want to temp fate for a fairly key part.
I run Tohatsu, but trust their OE parts to do the job. Plenty pattern parts out there on fleabay and such like, but not even remotely in the same league quality-wise. That's my tuppence worth.