You can't change the position of the dock but for themes there are some in official repositories.
Gnome-Look is the place for all your themes need.
There are some ppa's to install some famous themes and icon-set:
Equinox-Theme and Faenza-ICons
sudo add-apt-repository ppa:tiheum/equinox
sudo apt-get update
sudo apt-get install gtk2-engines-equinox equinox-theme faenza-icon-theme
Elementary theme/Icon
I think you get it from official repository.
Orta theme which also recommend Faenza Icons
sudo add-apt-repository ppa:nikount/orta-desktop
sudo apt-get update
sudo apt-get install orta-theme
I myself use Zukitwo with Faenza-Cupertino from webupd8-themes-ppa
For dock: There are also various choices in the official repositories like avant-window-navigator
or docky
or cairo-docks
Or a new and a simple dock plank
which can be installed from ppa
Reading state information... Done E: Unable to locate package orta-theme[/code] – NewUbuntu11.10Installed Dec 01 '11 at 14:28
oneiric
what you can do is installwebupd8-themes
ppa which includes a mintified orta theme i.e. default theme of Linux Mint. – sagarchalise Dec 01 '11 at 14:53orta
but from the same author for Linux Mint so its greenishsudo add-apt-repository ppa:webupd8team/themes && sudo apt-get update && sudo apt-get install mint-x-theme mint-z-theme
There are other themes on this repository as well you may try others as well – sagarchalise Dec 01 '11 at 17:16