I don't see what the point is of worrying about LTC/USD. The real index for LTC is LTC/BTC.

Be aware that these exchanges are highly manipulated.  It makes it fun, but can kill a bot that's not prepared to deal with outside the norm situations, such as the BTC rise on Gox last week.

I know you're saying BTCe but as far as I can tell BTCe shadows Gox and either the site has a trading bot that sets prices relative to Gox, or there are a few bots with lots of bank that are setting the prices.

Make sure and study the meteoric rise of LTC over a few days, that all started with a massive pump.  Then study Saturday 6th.  I was online at BTCe when some guys came in with big btc bank and bounced the charts a little to manipulate the prices.

If you can figure out the elasticity between Gox and BTCe that likely could yield great results.