Well, you're right. 800x480 is a very standard resolution, but we're talking about Motorola, right?
Having 854x480, you still keep one axis standard (480) which makes 800x480 applications easier to port.
Just google the different resolutions and you see which one's more popular and widely used:
resolution - hits
480x800: 365 000
800x480: 1 270 000
484x850: 73 000
850x484: 102 000
480x854: 80 200
854x480: 475 000 --
Astronomers have found an enormous void in space that measures nearly a billion light-years across.
It is empty of both normal matter — such as galaxies and stars — and the mysterious 'dark matter' that cannot be seen directly with telescopes. [...] But the void discovered by a University of Minnesota team is about 1,000 times the volume of what would be expected in typical cosmic gaps. [...] 'If you were to travel at the speed of light, it would take you several years to get to the nearest stars in our own Milky Way galaxy; but if you were to go to this hole and enter one side, you'd have to travel for a billion years before you would get to the other side,' he told BBC News.
"Kill the Wabbit, Kill the Wabbit, Kill the Wabbit!" -- Looney Tunes, "What's Opera Doc?" (1957, Chuck Jones)