How short is short?
My wife is Very Short and so she's now riding a small Soma Buena Vista mixte with 26" wheels. No disks but all-up weight is well under 10kg for a steel frame bike (and that's with mudguards, tiagra and 35mm bomb-proof tyres).
My next commuter might be a Raleigh RXS. 12mm through axles, hydro disks, nice aggressive position, frame designed for a belt drive, 9kg, £570. Only drawbacks - 1 gear, and UK import taxes.