new experimental feature: historic orderbook for all altcoins
blockchained does it with mtgox BTC orderbook bid/ask sums

LTC historic orderbook (scroll down)
http://www.cryptocoincharts.info/v2/coins/show/ltc

for now i am saving all pairs on altcoin exchanges. in the future i want to sum up the values of all exchanges to show a bigger historic orderbook but as first step i have to keep collecting data