More years ago than I care to remember I picked up a Kenwood D700 rig. Since I have recently pulled the HF rig and D-Star rig out of the car, I decided to put the Kenwood rig in for a while. Scrounging around I found a nice 5 hz GPS that has RS-232 (DB-9) output and made up an adapter cable from DB-9 to 2.5mm stereo plug to connect the GPS to the rig. It all seems to be working and http://aprs.fi is reporting my spots.
One downside of the D700 is that while it is a dual band rig, once you turn on APRS you pretty much lose the 2 metre side of the rig for communications. That's ok, since there are so many 23 cm repeaters in the area.