Cost was absolutely a factor. The Panavia Tornado was previously certified to carry US nuclear bombs. The same could have been done with the Eurofighter but Germany would have had to pay 100% of the program cost because no other NATO member was interested.
I can't see any scenario where France would agree to share nuclear weapons with Germany. The only approach that might work would be to forward deploy French nuclear forces on German territory, with Germany picking up the cost.
> The Panavia Tornado was previously certified to carry US nuclear bombs
During the cold war. That's a very important bit.
> The only approach that might work would be to forward deploy French nuclear forces on German territor
Are you sure you know how the current program works? Because that's how it does. The US aren't sharing nukes right now (that would violate NPT), the plan would be to hand off the weapons to its allies in the event of an invasion.
I can't see any scenario where France would agree to share nuclear weapons with Germany. The only approach that might work would be to forward deploy French nuclear forces on German territory, with Germany picking up the cost.