Hi Jens,
No I don't have any hard-disks for my Atari, but have some SCSI and IDE hardrive of different size that I'm not using and I think that it could be cool to connect one of those on my Ataris (520 ST & 800 XL) to store some of my programs & games.
I have found a way to connect an IDE HD to my 800 XL using the interface from M. Atari. But for my 520 ST I still didn't get anything to connect it to an HD.
Thanks for the link. I have seen that they have some products to connect my ST to an SCSI HD but I'm not sure wich product I need as this website is in German and I don't speak german ;-p