Designers Guisset Constance & Cid Grégory have a fantastic concept for a space-saving triple trashcan that looks like it'd even fit in my minuscule London kitchen.
The left pedal opens the highest can in a traditional way. This can is for general discarding. A bag dispenser is available here. The middle pedal makes the second can rotate around a decentered axe. This can is for packaging, plastic etc. The right pedal makes the last can move towards the user. The last can is for glass discarding.