Virtuemart2 custom field plugin

We need to have developed a virtuemart2 plugin for custom field. We will start from a free dropdown plugin, to build a more functional one. It will do : - combine one or more other custom field ( eg. Color and Size ) - give each combination a sku, a check to publish or not ( instead of stock control), and additional price. ( eg . White - Small - qty 0 - priceVariation +1 ) - option to assign pictures to variants ( f.e. currently displaying white in frontend --> [login to view URL] ) Remember it have to be displayed in frontend, so we need to build a bit of template in it self. Only experienced freelancers, for past bad experiences, and as you can see many incomplete project and time wasted. Chances to increase work, as we need around 20 extensions for all our website, to pass this as a future hourly budget colaboration. Thanks