I've also been contemplating Android head unit, as mine is non-navi anyway. Check out the Pakwheels online shop and there are a couple of Android units listed there. Lots of variety on AliExpress also, including huge Tesla style units.
But I've been held back mainly due to aesthetics. They have D button on left side for dual climate control and P button on right side. The buttons illumination should also be matching orange so that it blends in. Same for the plastic finish of the unit. If all these things are not right then the unit will clearly look out of place in the dashboard.