After checking out a few in Leh’s libraries, the best map I found was the Julley Ladakh Trekking & Road Map, which turned out to be a really great map, with main roads and smaller roads, trekking paths & villages to stop at, temples and monateries, passes heights, military checkpoints, etc… Even indications on mobile network.
Devil on Wheels website is very documented, with taxi rates, up to date status of roads, lots of information for motorbike riders, blog and forums often updated.
The Lonely Planet has a fairly complete chapter on Jammu & Kashmir, with lots of information on Ladakh. You can buy just the one chapter electronically, either as a PDF or on your e-book or smartphone, which ends up being pretty handy.
The Rough Guide also offers this service, but it seems you have to buy the whole book. I actually met the writer for Kashmir on my trip, so I can only advise you to try it. I mostly used it on my first trip to India, in Delhi, Rajasthan, Punjab, UP, Kolkata, and I really enjoyed it.