I assume you mean something to trigger the camera, right? I was in the same boat - I really liked the little Canon RC-1 IR trigger, but while that works with the 5DIII, the 1-series bodies don't have an IR receiver so a radio trigger was the only option. Canon has an LC-5, it's expensive but for me the real downside was the remote unit is really big.
I picked up a hähnel Giga T Pro II RF remote. Interval timer, the remote unit is small enough to fit in the palm (for getting in the picture if needed). I like that the remote unit can actually be plugged directly into the camera if desired (i.e. used as a wired release) for interval timing, etc.
If you do have the Canon -RT system, you can acutally use that to remotely trigger the camera - but using a speedlite or ST-E3 as a handheld remote isn't the most convenient option, IMO.