The name Libretto might ring a few bells. Toshiba introduced a miniature range of portable computers with this name back in 1996, initially in Japan. The Libretto arrived in Europe in 1997, but was subsequently dropped from Toshiba's product line-up. Now it has returned as an ultra-ultraportable that packs in a remarkably full set of features. However, the Libretto U100 is expensive at £1,249 (ex. VAT), so for the money needs to be a fully functional notebook. Does it deliver?