This isn't the best solution, but you could also create a field in your Category table called Template_Version and set it to either 'A' or 'B' for specific categories. Then on the custom category template page where you want two versions, you can place the following:

<%if Template_Version eq 'A'%>
Full HTML for Version A Page Here

<%elseif Template_Version eq 'B'%>
Full HTML for Version B Page Here

<%endif%>

This would allow you to have two versions of the this category page depending on the version you designate in the Template_Version field. You would have to be careful with this, that you do designate a template version for each category.

--FrankM