well, with some simple maths and a bit of google you can get that kind of range off any radio! what you have to do, is work out how long the wavelength of whatever frequency you're on (say band 4, 27.145mhz i think) and cut a length of antenna wire (i seem to remember 10 ohms from somewhere) to that length (to the nearest millimetre though!) and your range should be hugely increased. of course, it limits how portable your radio is, but i guess if you need that kind of range it doesnt need to be too portable. of course, if space is an issue you may need a telescopic antenna support to attatch it to, or you can halve the length of the arial. and its still legal because you're still outputting the same power!
HPI E-Firestorm - Tamiya TA05 racer (carbon chassis, 10.5 brushless etc) - LRP Blast S10 BX - Revo 2.5r truggy conversion (in progress)