I'm pretty sure you could use an 8-bit IDE card in an XT, unless it looks at the wrong address to boot?
XT IDE/XTA info: http://nerdlypleasures.blogspot.com/2014/04/t … erface.html?m=1
Example I found on the not to be spoken auction site.. Made by Seagate with the same drive in it you mention. I think the controller is a Seagate ST05X.
Edit, according to Seagate, the ST05X controller works on an IBM XT class computer. ftp://ftp.seagate.com/techsuppt/controllers/st05.txt
This text document isn't the exact board described, but it uses the same disk controller chip, so it should work according to their documentation.
Juko also makes a XT class IDE controller I know of, but I have never come across one. A Philips 8088 board I have has a built in IDE controller. I think it uses the same chip as the Juko if I'm not mistaken.