Sell separate packs of just gun crews for all your lines. They can be used for larger gun teams or as crew for SP guns.
You can request non-standard items, like a bag of gun crews, at the moment. I've done it myself. It may cost marginally more than a standard pack but it's something Leon and Co. do regularly.
I'm sure he's said in the past that he aimed to do packs of artillerymen as standard but with a million and one other things to do it may not be highest priority, given there's an alternative already.
The man himself my wish to correct me :)
Again Himself may wish to correct but it's likley that the gun and crew will be in the same mold, which is one reason for the extra cost.
Gun crew packs is a good idea, properly equipped and serving a gun in a realistic manner, rather than what seem to be something of after thoughts at present, plus ready rounds to 'decorate' the base.
Yep, we've got this on the plan for later in the year. I want to revamp all of the WWII crews with both 'small' and 'large' gun crews in more suitable poses, and we'll be adding these to the site as a separate code.