you should be able to index the way you want. In contrib there a module "cube" which does similar to what you want to 3D, extending it to 12D shouldn't be too hard...
contrib/cube module implements N dimensional cube representation -- Teodor Sigaev E-mail: [EMAIL PROTECTED] WWW: http://www.sigaev.ru/ ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq