Temp cover for under 21

Isn't there one single company or broker that will insure me for 1-28 days. I am 19 years old and I'm considering buying my uncle's car but wanted to insure it on Friday (27th feb 09) for about 10 days but I would insure it for one month also if I could do that but everywhere seems to say 21+, does anybody know of somewhere or a number of a company that will do this? I would be so grateful if somebody could tell me where I could do this.

Thanks Nathan