Wave 6 needs to include this 4 specific ships. The theme being X-Wing vs. TIE Fighter
IMPERIALS:
Assault Gunboat - http://fractalsponge.net/gallery/Starfighters/XG1%20StarWing%20Assault%20Gunboat/slides/g1.jpg
TIE Avenger - http://d6holocron.com/wiki/images/thumb/f/ff/TIE-ad-Advanced-Avenger1.jpg/500px-TIE-ad-Advanced-Avenger1.jpg
REBELS:
R-41 - Starchaser - http://img4.wikia.nocookie.net/__cb20060309133841/starwars/images/f/f7/R41-XWA-3dRender.jpg
T-Wing - http://img1.wikia.nocookie.net/__cb20120612165642/starwars/images/7/7f/T-wingStyles.jpg
In addition to these ships, each expansion should contain a pilot card for a Large Ship from previous waves. These pilot cards will be the opposite team of their given faction. As we have seen in games like X-Wing and TIE Fighter, the game included such ships as the Lambda but designated to the rebels. The YT-1300 were also used by Empire friendly smugglers.
Perhaps also, there could be a unique pilot and one non-unique pilot per ship expansion pack: example: Lambda Class Shuttle card called "Shuttle Tydirium"
The idea of a YT-1300 being escorted by a 4 TIE flight is very intriguing.
Edited by Boundary