I personally don't believe in god but I think that this is an interesting debate.
My take on it is that everything moves at an atomic level, the little beggars are vibrating like mad. God created the laws of physics that govern this type of behaviour. Therefore if god created a rock in THIS universe, no matter how big, it would always be moving due to the forces he ordained will be applied to it.
OK, so he creates a rock so cold that all atomic activity has come to a standstill (not sure if this is possible as electrons would probably still orbit the nucleus but that's beside the point). So, he's made this really big cold rock, now earth is moving around the sun, the sun is moving as part of the expanding universe, etc, etc. So everything else in the universe is moving about, this means that the rock is moving as well, i.e. it's place in the the universe is changing relative to EVERYTHING around it. All movement is relative depending on where you are looking from.
God, well he's everywhere so he only has to move the "everywhere" to move this rock, as all movement is relative and if everywhere is moving then the rock, in relation to everywhere else, is moving also.
So creating and moving the rock is not a problem, stopping it may be though.
I think all this going round in circles proves that physics isn't the best way to discuss your god.