I'm not getting the precise reason you are limiting your lens to 60mm. Canon, and Tamron both make lenses in the 60mm range, but both are for cropped sensors, like the sensor in your 650D. If your going to do macro work, just add some extension tubes to a macro lens. This will diminish the minimal working distance from the lenses outer element. I did look at the Sigma catalog and noticed a Sigma 70mm f2.8 Ex DG that is designed for full frame, and cropped sensor cameras, with a angle of view of appx. 105mm. That lens will also be a true macro, 1:1 with a 10.1 inch minimum focusing distance. You may want to look at Zeiss, those lenses are just to expensive for me to keep a catalog handy.
BTW, Canon does produce a 60mm macro, but is know as EF-S 60mm f2.8 macro USM. This lens will only mount to your 650D.