I have used bidz.com, used it quite a bit a year or so ago when they had free shipping to Oz between certain hours.
Never made a killing on ebay with the items, but did ok. I see the ebay market completely flooded with bidz items now, so I would have to doubt if there was much in it now.
We found the true online market value of most of their items to be around 10-15% of the value they quote on the sale. We would only buy if we could secure the item at around 5-7% of their estimated value to ensure some profit, but that was back then.
You say dropshipping, but bidz was never a dropshipper, just an auction, I'm assuming there has been some serious changes over there so I'll have to stop by for a look.