by looking at your forum, since the style "bayskate layout" seems to have the header made differently, you would need to keep the template set seperate from the others.
templates are the actual HTML bits the forum code puts together, the code assembles the bits and puts in the information, then sends it to the browser.
if your styles had EXACTLY the same layout in the templates (i.e. whenevery you edited a template, you have always done all 3), then all you would need to do is go to
edit style properties under
styles and choose a template set for each one. Make them all the same set, and when you have all 3 styles using the same template set, then you can delete the others. This will leave only one template set to use. All images and colors will remain different.
if there's any difference that you've put in the templates to make the styles look different, then it would be best to keep a seperate template for each style.
I can't really explain if further.. if it's still too much trouble, best thing to do is to stick it out and wait for vb3, which will give you the ability to edit all templates at once