Wrapping your URL in [mixcloud] or [sc] tags will do the trick for embedding content from Mixcloud or Soundcloud. [bc] for Bandcamp also now working. Bit messy because you need to manually extract the track ID from the embed code, but it works.
[sc]http://soundcloud.com/ooal/come-wanader-with-me[/sc]
[scpl]http://soundcloud.com/ooal/sets/hidden-highways-hidden-1/[/scpl]
[bc]1824928865[/bc]
[bclp]708531060[/bclp]
[mixcloud]http://www.mixcloud.com/feedmeweirdthings/dark-skies/[/mixcloud]
[muzu]566087[/muzu]
[sc]http://soundcloud.com/ooal/come-wanader-with-me[/sc]
PHP:
[sc]http://soundcloud.com/ooal/come-wanader-with-me[/sc]
[scpl]http://soundcloud.com/ooal/sets/hidden-highways-hidden-1/[/scpl]
PHP:
[scpl]http://soundcloud.com/ooal/sets/hidden-highways-hidden-1/[/scpl]
[bc]1824928865[/bc]
PHP:
[bc]1824928865[/bc]
[bclp]708531060[/bclp]
PHP:
[bclp]708531060[/bclp]
[mixcloud]http://www.mixcloud.com/feedmeweirdthings/dark-skies/[/mixcloud]
PHP:
[mixcloud]http://www.mixcloud.com/feedmeweirdthings/dark-skies/[/mixcloud]
[muzu]566087[/muzu]
PHP:
[muzu]566087[/muzu]