The listing stated that he would sell it for the first $1800 right at the top of the description. He probably got offered that much within hours of listing it. It does sound like a very rare A4000T, maybe even rarer than the commodore ones. A motherboard with slots for 128mb of ram and an 060 processor card with slots for another 512mb. They didn't make very many of those.
Perhaps, but if he got his immediate offer of $1800, it would still be listed but as a Closed/Finished auction, and Ebay would not have sent out the email saying it was "REMOVED".
The ebay email implies that EBAY removed the listing, not the seller.