I've had an idea for a map which goes something like this.
Each player starts at the end of a chain of planets leading to the local star (the size of the chain and whether they lead to the same star can be tweaked). The first player who reaches the local star has a small advantage, so that keeps the pressure on.
However - and here we have the twist - every single planet in the chain is heavily populated by Pirates. And also (this is important) the planets themselves become increasingly heavily fortified as you reach the local star.
Is this doable? Has it been done?
Oh, erm, Entrenchment naturally. 
