I certainly don't see any need for any special reporting.
You say you buy product for resale, so your COGS is certainly going to be reported in the usual fashion:
COGS = Opening inventory (including unsold items out on consignment) + Purchases - Ending inventory (including unsold items out on consignment)
You report you sales as the sum of "My direct sales" and "Sales via consignment", a summary number that makes no distinction between who actually "made" the sale.
