So it turns out that the guy at the local electronics store near the
university is too damn cheap to lend me a crimp tool for literally 10
seconds, and would rather charge me $5 to merely crimp a header onto the
end of a cable. So I decided to crimp the modular header (for ICD) onto
a the cable myself. I decided to instead use a flat ribbon cable (like
the computer IDE cable) since they're thinner and much more flexible
than the 6 wire telephone cable I bought. The wire-to-wire pitch is
slightly larger than for a normal telephone type (6p6c) cable so you
can't insert it directly, but if you pull the individual wires apart to
about 5mm from the end, and then put them in, it works out well.
Crimping without a tool was a snap - took only about a minute with
nothing more than a flat head screwdriver to push in the tab as well as
each of the contacts.