Magma made up their own singing language, such a weird and interesting band, though might inspire http://www.youtube.com/watch?feature=pl ZZ68i_TE2U
Sigur Ros use to sing in Hopelandic, an unintelligible version of Icelandic that Jonsi made up just for singing.
Im certain Cocteau Twins/Elizabeth Fraser did something similar with incomprehensible lyrics aswell.
Im digging Magma
Ruins (one of my faves) also sing in Kobaïan.
joe papa from controlled bleeding scats like german website man.
ruins also one of my faves. they are visiting chicago in a month cant wait!!!!