Actually, Fatman Fabs has a kit out that modifies newer (SN95) front suspension for classic mustangs. It's designed for '94+, but probably could work with the older items. And Fatman has a pretty good rep for their other setups.
One problem with the kit is the price. $2k and you still need to come up with spindles, struts, and a rack (not a problem for you). RRS Online has a similar setup as well (starts at $2600 -more complete, and I think TCP might have a setup as well.
Some people, myself included, have been attempting kits on their own to do the same thing, for much cheaper (I'm hoping $1k total). Check out posts by MrPantera on VMF, he somewhat details his project. Unfortunately, he's been out a while and hasn't updated. I haven't completed my project yet, but will post a detailed workup when I finish (want to make sure it will work first) - hopefully beginning of the year.