Without being a dual-timer watch, the Timex Ironman can do "laps." You press a button and it starts a new "segment" of the timed event. You can have the watch display your lap (segment) time in small digits with the total time in big digits, or the total time in small digits with the lap time in big digits. I love the latter setting because it feels like I've just been running for 3-4 minutes.

There is a Timex Ironman watch with a heart rate monitor. It looks pretty good.

There is also a Polar model (but not the F4 I think, unless they changed it) that separates laps.

I currently have a F4 and a Timex Ironman without HRM. I've been caught wearing the two at the same time once.