I used a pair of these and had them professionally trimmed in black leather -
http://www.ebay.co.uk/itm/Dax-AC-Cob...item1e9a638624
I just gave the trimmer a picture of some old Porsche 356 coupe seats that I liked and they made the covers to match them -
They're very comfortable, give a laid back driving position and worked out a damned sight cheaper than those from Holden (which also look a bit too upright and thick in the squab to work in a Sammio imho).