The point of ASCII- and intelhex- based bootloaders is that you can program the chips with any serial terminal capable tool.
I know little on WinCE and its descendants, but I believe that there is something similar to Hyperterminal there. All it needs to have is a textfile upload option and a delay after each line (see the datasheet for the max.programming time).
Somebody here also mentioned a trick, to have prepared a couple of short files, containing only one intelhex record each, for erasing, setting the flags etc.

Oh yes, not so convenient as FLIP, but working...

Jan Waclawek