Army Camp Boost

Perhaps it could be possible to temporarily increase the capacity of an army camp, maybe by 5 or so spaces at the cost of about 8-10 gems. This boost would not take a set amount of time, but instead just 1 raid. Maybe it could only be done to 1 army camp at a time, or something of the nature of that. Let's say I did the boost and my troop capacity is 150, but I only took up 75 spaces and did an attack. Even though I didn't make use of those extra spots, I would lose my upgrade, since it only lasts one raid.

Thanks!