Joomla templates are actually available all over the web. Just make sure that whatever template you decide to use works with the version of Joomla that you have. At the current time, themes are available for both the Joomla 1.0.X and Joomla 1.5.X.
There are two different formats of this software guides. They are back end templates and front end templates. The back end templates will help you to define the layout and style of the side of the website that you, the webmaster, administrator and / or editor will see. The front end templates define the layout and style that any visitor to the website will see.
You can acquire some of these guides in three different ways. You can either acquire them by purchase, you can write your own or you can acquire them for free. There are actually a lot of different websites that are available for both commercial templates or free templates and websites that contain both. All you have to do is search for them.
This program is an open source software, which means that anyone can write extensions of the software and they will work with the initial core components. Because of this reason there are quite a large number of extensions like modules, themes, plugins available to work with the core functionality of the this version. You can even write your own, but knowledge is HTML and CSS is a must, unless you have that special software where you can just plug in the information and the rest is done for you.
This version of these 1.0 themes come in every shape, form, color, and style that you can imagine. I'm sure that if you look long enough, you will find that special theme that you have been looking for. Whether through purchase or free acquisition, you can download any one that you want off of the many websites that are available on the internet that are dedicated to offering the public Joomla 1.0 guides. Again, just make sure that the template that you choose is a 1.0 version and not a 1.5 version. Do not get confused between the two different versions of some of these themes.
If you still can not find that perfect theme that will give your website the look, feel, and style that is desired, consider either writing your own or hiring a designer to write one for you. The thing about acquiring a template through the web is that nine chances out of ten, the layout and style is probably already in use at at least one more website if not thousands. If you want your site to have a different feel and look than all the others and you want a truly unique website, then this is the route to take. I would only advise you to write your own if you have the proper software that will help you; otherwise, you can get confused and mixed up as all the files and extensions for Joomla have to be designed and written a certain way to get them to work. If you have experience with HTML and CSS and know a little about compressed files and extensions, there is a good chance that you could write your own version of the template.