I'm not sure if it's kept or tracked anywhere, but would it be possible to see a list of what people are bidding on your items? For example, if I put up a rare +1 sword that hasn't sold in a few weeks. I might try to bump the price up say 50-100k. It'd be nice to see if 1. anyone was bidding on the item at all. 2. What they were bidding. Instead of my price of say 500k, someone might be bidding 400-450k. If I could see that's what the market is willing to pay, I could adjust my prices accordingly.
I'm not sure what would be involved to do something like that, but if it's a complete pain, maybe just track the losing bids for items say over 50 or maybe 100k. Just a thought.