Book on homebrew 68000 system
I think tcrosley is on the right track with it being a hobbyist newsletter but the same small company that published it also sold 68000 co-processor boards using the DTACK name. There is a site here that has copies of some of the newsletters and the May 1985 edition contains the following price list:

YE DTACK GROUNDED PRICE LIST
DTACK Grande: 12.5MHz 68000:
(for Apple II, 1 wait state)
less aux. bd:  with aux. bd:
128K   $650      640K   $925
256K   $690      768K   $965
384K   $730      896K  $1005
512K   $770     1024K  $1045

Interestingly despite the name it mentions having one wait state so I'm not sure they ever achieved the DTACK grounded aim using memory technology of the day. I remember seeing their advertisements in a couple of magazines so that's probably where you recall the name from. I don't recall a design being released and the following is near the bottom of the price list:

(Like HP, DEC and Wang we consider our CPU circuitry proprietary)