An open forum user managed to get his 30gig working on his 760X series thinkpad.  
5-feb-03    
  Glowing Success !!!
760XD can Recognize 30GB Hard Drive!!

Tricks:
1. Use Diskmanager 2000 (free download from IBM) to
low-level Format drive to less than 5GB (I used 9,000
sectors)on another computer.
You must used the Advanced option of Diskmanager 2000. If
you try to use the 760XD to do the latter, it Wont boot at
all, even from the floppy....

2. Insert drive into 760XD, and boot off the Diskmanager
2000 floppy, at which time a BIOS overlay will be applied.

3) Re-boot and insert a copy of your Win98SE boot disk into
the floppy when prompted.

4) Install 98SE onto your new huge 30GB hard drive!!

No warranty, I have not tried this one. Nor could I find a copy
of DISKMANAGER 2000 on what is left of the IBM storage
systems web site. The most recent file from the HITACHI site is
below. This file in on my FTP site.

  
RETURN Download DISK MANAGER 9.61.06 Here