You pretty much lost out on this one pal. Ebay's dispute system is indirectly designed to only help crooks. You really should have waited to have the cabinet in hand before buying those other things. Sucks for you, but he isn't responsible for that at all. You can try to guilt him, but apparently he is a guiltless bastard anyways.
Still, report him for breach of contract. He might have made an honest error, (doubt it though, he was just trying to save on fee's and got caught.) but if it was an error he had PLENTY of time to catch it before end of auction.
My opinion is if the guy is being a jackoff, then have at it with the complaints to ebay. If he is being sincerely apologetic, just let it go with neutral feedback. I remember when I thought I bought an Ipac4, when I really overpayed for an Ipac2. The seller could have held me to it, but he was cool after I explained to him my mistake. We mutually withdrew from the deal and he got his fee's back to relist.