I think $1,000 will come sooner than later. More interesting question is, when one BTC costs $1,000+ USD, how much will LTC worth?
Most likely around $2, why should LTC be worth more just because BTC is ?
Most likely $20, because the LTC/BTC ratio will probably stay the same.
I do not think so. Due to the fact that there will be four times as much Litecoins as Bitcoins the value ratio should konverge to that sooner or later (probably later). Currently no cryptocurrency (CC) is mainstream so none of the current values (fx rates etc.) is stable or represents anything measurable. That may change within the next two years if Bitcoin gives a proof of stability and acceptance.
Then the next question is what will happen to the next introduced cryptocurrency (or the ballpark of the currently existing ones)
Why do you think that all LTCs should be worth as much as all BTCs? I would assume that a currency is a natural monopoly because you want to use what others use. Which would mean non btc cryptocurrencies would go toward zero in the long run, I can't see anyone overtaking.