It all depends on the marked you are trading, on the bigger future indexed 100 lots will not be a problem, but 1000 lots will give you some slippage even on the biggest markeds.
Why do you want to know, if you had the money for that amount you would know the answer. As far as I can tell if you hit 1000 on one hit you may not get them all on immediately,depending on time of day and volatility etc,but the remainder would stay there until the market went through you price. If it didnt go through then all the contracts you got would be in profit so either way the answer is yes they would all get taken or youd have a nice profit.. On forex with good brokers the amount available is often shown on screen in $