Very, very good point. Interlnk and Intersrv do work, and work quite well. They only came (AFAIK) with DOS 6.2. I use it on that old IBM laptop between it and another computer when I don't want to pull out the drive and move it over.
Again, if you use it go with the parallel cable, and set both BIOS parallel ports to their fastest speed (EPP / ECP). Serial is way slower.
You can even run Intersrv from inside a DOS box in Windows. This way if you have any Windows-only supported drives you can still access them.
Pulling out the HD is no problem on IBM laptops (I have 3) - it's so easy it shouldn't void the warranty, should it??
Which IBM do you have? If it is a new one the drive is inside a small mu-metal 'carrier' that pulls out easily. Once outside the laptop the IDE connector is directly accessible - just add the cable. IFAIK they couldn't even tell. Anyway, the HD is upgradable. And if you upgraded...
I have a 755c, a 701c Butteryfly, and a 390e. Love them all and do quite a bit of drive swapping as the (2) old units don't have CD. So, so easy.
Your mileage may vary...