See:
contacts on desktop sorter
At the moment 'change transparency' and 'hide when offline' are the only options.
Altering the position would be too complicated. There'd probably be bugs which resulted in positioning them in the wrong location. It'd have to be a fixed location Plus! positioned them in, either that or an options panel which you input co-ordinates, as well as how much spacing in between each contact, which again is complicated and unneeded.