OM10 bodies have a patchy reputation - if the circuit board dies (and they do, like all electronic cameras) the camera is dead and repairs are hard. If you really want an OM body, a 2n would be a better option. But it will only lead you into temptation.
Unless you can show a compelling reason for the hardware, I'd put the money towards film. You have to feed that 645 somehow. Starving a camera is a serious crime, you know!