Coldcloning Win98 is very easy.
Boot the machine into a Knoppix CD and attach a USB-disk.
clone disk to USB with a command like this:
dd if=/dev/sda of=/mnt/usb/win98-flat.vmdk bs=1M
when that is done post the size of the win98-flat.vmdk and I create a descriptor-vmdk file for you.
Then upload both files to the new ESXi or Workstation host and add them to a new Win98 VM.
Regarding drivers ... - in most cases it is enough to cross your fingers during first boot and have your Win98 Install CD ready at hand.
Creating a MOA CD for this task is not really necessary as Converter will not help you with Win9x imports.