Air 2000 have 3 new B757-28A aircraft scheduled for delivery in March and April this year, details as follows;
As far as I know they are the only airline with B757-200s on order, so the aircraft you saw is almost certainly for them. The final aircraft they have on order is G-OOBF C/N 33101 is due for delivery in April 2004. Let's hope the B757-200 gets some more orders before then!
Take it the aircraft isn't painted up in the new scheme yet?