Below you can see the front view size comparison of Canon 60D and Canon 50D. Canon 60D is 1mm narrower and 2mm shorter than Canon 50D but it is also 5mm thicker.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon 60D is 67g lighter than the Canon 50D but we don't think this will make a significant difference.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since both Canon 60D and Canon 50D have the same APS-C sized sensor, their lenses for a similar focal length and aperture will be similar in size and weight.