David, aka BadWolf is working on a new project. maybe this would an option for you: https://www.youtube.com/watch?v=pU4Z5ZRTrIU

Or, if you know how to solder ACSI2SD: https://www.eltradec.eu/index.php/de/w/7914

The both lay flat on the backside of the ST

Do you need some kind of hdd or would work a gotek too?

As far as i know, he Lightning ST is still avail. If you have an account at forum.atari-home.de , you can write gaga a pm about it. Dont blame me if i’m wrong but i think it was around 100 bucks