Every things seems to be perfect except this line
It will have a Designer tool for (Shirts, trousers, chinos and Polos). what does it mean designer tool- do you mean flash, javascript, ajax or what and what will be the functionality of designer tool???
I am comfortable to work with joomla, oscommerce, magento and interspire but in my opinion only joomla will fit better as it also has a inbuilt cms with it. For magento to have a cms you need to pay a license of 1299 USD per year.
Joomla will fit the best in this cart- only need to understand is your designer tool. Please explain in details. Other wise i have some very good designs for cloths shop and tailor shops in joomla, magento, oscommerce etc.
regards