Only if you have one image for each type/colour combo...
But, I'm working on a project called Liquid. It was created by Naltabyte AB and contains a lot of functions for easily creating tons of applications and neat effects on a site. Everything is built up using custom XML tags and works just like plain HTML except for the fact that it can be dynamically changed and animated. Some tags (like the <drag> tag) are even interactive).
The part I'm working on is called Draw. It is a 2D vector graphics engine which can be used to draw and fill any polygon, using a single XML tag.
Draw displays the images using <div> tags so the user can view the images even though he/she has disabled images!
The images can be generated on the server and passed to the client in about the same time a normal image would take to display.
With this technology you could draw a polygon for each shirt type and let the user choose the colour from a drop-down menu or something like that. After each change, the client passes a request to the server which regenerates the polygon with the new colour and sends it back to the client.
You can also change which shirt type the polygon will look like by replacing other tag-attributes such as path, or zoom...
You could even have things like Logos and stuff on the shirt by letting Draw fill the polygon with an image and position it wherever you want or repeat it all over the polygon... (The space not taken up by the images is filled with a background colour, including transparent areas in gifs.)
More info about Liquid can be found on
www.naltabyte.com
More info about Draw can be found on
www.naltabyte.com/draw if there's no link from the first page...