The A4000T looked too much like a commodity machine (cost-cutting measure?). It felt very different from the rest of the Amiga line-up. Especially, as the A3000T looked more like a Unix workstation and did not have the baydoor. I did see them advertised in CU Amiga, but they were too expensive. It was aimed at the higher-end due to the inclusion of an internal SCSI interface, and plenty of space to have VideoToaster and disks installed. However, most A4000s I worked on/seen, were all the regular desktop case.

https://en.wikipedia.org/wiki/Amiga_4000T states the following about the case:

""" The case itself was a re-purposed PC case which is evidenced by the presence of the Turbo button whose function in A4000T was to disable the internal speaker """

https://bigbookofamigahardware.com/bboah/product.aspx?id=31 states:

""" The A4000T from Commodore only saw a limited production of machines (estimated at 100-200) before they went bust in 1994, most machines never made it to the market but ended at third party developers and the local Commodore companies. A recent BBoAH study (2013), indicates that the number machines still existing is VERY low (only a handfull of named owners has been found so far).

In an email from 1996 send from Peter Kittel to a german A4000T user, Peter wrote "that only ~35 Machines got deliverd WORKING to customers, ~35 where NOT working. All in all only ~70 machines left Commodore for customers." That would explain why it is so hard to find somebody owning such a machine. For this reason the Commodore Amiga 4000T is considered the rarest commercial available home computers ever made. """