Buy or Sell 1000+ Btc in a time is not a joke , it will Boooom the market, also anybody will not deal with you with these Conditions, if you are really a serious buyer you can buy this value of bitcoin from some trustable exchange , for example you can buy 5 Btc from 10 exchanger a day  ( that's mean 50 btc a day ) so you can buy those 1000 Btc just in 20 days