Axsapt Matrix for Advanced Business Manager is a powerful extension that manages multi-dimensional products such as Clothing which has Colour/Size/Season attributes.
Rather than having to enter each individual product as a separate line item in your current accounting system, Matrix presents you with a Matrix Grid with the Colours on the Rows and Sizes on the Columns.
Reports are also formatted in this way so you can see at a glance Sales and Stock results by Styles with associated Colours and Sizes.