I bought a 3m (9ft) USB cable for 0.99 GBP on ebay, the seller said they could make them any length. A local computer shop could do this also if you needed a particular length.

Very handy too is a retractable USB cable, usually sold for laptops, measures about 1m (3ft). When not in use it is not hanging all over, quite discrete for home use, the cabling in these is narrow, flat, I'm not sure of the durability.