are there anyone exchange not instant in bitcoin withdrawals/deposits??
Some smaller exchanges require 6 confirmations for BTC deposits, larger ones require 3 confirmations, while some let you trade even after 1 deposit.
However, BTC-E requires 6 confirmations for LTC deposits at the same time demanding reasonable 3 for BTC. Only BTC-E managers know why, they probably think LTC is not safe after 3 confirms but that's nonsense, nobody can double spend LTC after 3 confirmations, and even if somebody could do it he certainly will not try it on BTC-E deposit.