If that IDE bridge doesn't work for Macintosh for some reason, and you don't mind having external hard drive consider early PowerPC based Powerbook like Wallstreet or Duo 2300. They support IDE drive internally, can work with $5 CF to IDE adapter, and can be connected via SCSI cable to another Macintosh.  For a "permanent" hard drive laptop, take out the keyboard, find which 2 wires in the matrix correspond to letter T, and wire in the motherboard's keyboard connector so it'd act like T key is always pressed, this will force the Powerbook to boot in disk mode. Don't need an OS for it and many of the early Powerbooks (such as 1400, 3400, 5300, and Wallstreet) should work.