oh yea… good question.
i think in terms of cost you can only choose either blank or pips on the other sides and i think they should be pips because of house rules where a two result would result in a damaged bomber ( it returns back to base and does not perform mission).
If cost is included for a unique image on the other 5 sides, then something like the same image with flak bursts on 5 sides, and a bomber blowing up on the one result?
I have a new idea: technology dice! The dice could have an image of a wheel of industry or the standard flask and science desk setup or you have 2 dice: 1 with the tech image for success, then a second die that has the different techs on each side?
I know its kinda wild.
You could also make general dice for each nation: each side has a unigue combat modifier you roll each turn for one battle
examples:
1= defender can retreat
2= attacker +1
3= defender +1
4= Entrenched defense ( this would be all hits rounded in half – 5 hits is actually 2 hits)
5= Surprise attack +2
6= attacker repulsed ( they must retreat)
these generals dice would be used a number of times during the game… like 2-3 times per game or the dice can be purchased like a special action like paratroopers?
just ideas…
also you can have a winter die for unique winter results that may effect a region of the map
lastly, you can have a die that functions for sea invasions where the invading side needs to roll to see if the tides allow a landing.