Hi Darren,

I found a solution for this in V10, refer the app https://www.odoo.com/apps/modules/10.0/product_variant_supplierinfo/

and you have to inherit their views/product_supplierinfo_view.xml form view like below,

<record id="product_supplierinfo_form_view" model="ir.ui.view">
    <field name="inherit_id" ref="product.product_supplierinfo_form_view"/>
    <field name="model">product.supplierinfo</field>
    <field name="arch" type="xml">
        <field name="product_id" position="replace">
            <field name="product_id"
                   domain="[('product_tmpl_id', '=', parent.id)]"
                   invisible="context.get('hide_product_id')"/>
        </field>
   </field>
</record>

After this, I can able set the variant cost price in the variant window, then this cost showing in a purchase order of that variant to the vendor.

Hope this help you.

No we have had no solution for this issue