BBC Radio 4's flagship current affairs programme, Today, had an interview with Gen Sir Mike Jackson (infamous for refusing Wesley Clark's order to use force on Russian troops at Pristina airport). He also seems to have heard that Kosovo's bordered were expanded at Serbia's expense in 1960's to include the Mitrovica and more importantly the Trepca mining complex.

Audio here: http://www.yugofile.co.uk/mp3s/20071211_today_kosmet_boundary.mp3
Transcript follows:
BBC (Sarah Montague): One of the things you have suggested is possibly changing the boundaries... General Sir Michael Jackson: Well, I put that forward for what it's worth. I'm sure Mr Ahtisaari will have looked at it, but it does seem to me that northern Kosovo, north of the river Ibar, Mitrovica, the town of Mitrovica, that area is almost entirely Serb. My understanding is that that area - which is relatively small - was, is not part of historic Kosovo. It was "moved" from Serbia to Kosovo by an administrative order of Tito sometime, I think, in the mid sixties.