This is a query on behalf of a friend: is there such a thing as cable-operated disc brake levers with adjustable reach?
She's got Avid cable discs of some description, but the levers are stupidly big with a large default reach - not ideal for someone with small hands - even I'd find them uncomfortable and I'm nearly 6 foot!
Just a thought, a cursory search didn't bring anything up.
In that case you'll probably get something a bit cheaper maybe Tektro, Clarks, or something unbranded but these should do the job assuming the existing levers aren't attached to the shifters.
Those look more sensible - when I posted yesterday, I couldn't get onto the CRC website for some reason and hadn't found anything suitable in stock at the other big players.