Here is my favourite ABBA related mashup: 'Is There A Soul Out There' by Fissunix. It uses Duffy's Stepping Stone as a backing track along with Gimme Gimme Gimme's vocals to create a cool and contemporary, eery and atmospheric new song. In a flash of inspiration the YouTube uploader 2Shaymcn has set the track to the video of TDBYC. The slowed down train station and carriage interactions work particularly well.
It's 21st Century ABBA! What do you reckon? And why not post your own favourite mashup or 3rd party remix featuring ABBA?