Paying for wall upgrades

Good afternoon everyone....first post! I looked over the sticky's about already requested and ruled out suggestions and I didn't notice anything like this request. With the L10 & L11 walls being so expensive, how about allowing the option to combine resources to purchase them? An example would be if you wanted to upgrade a wall section to L10 but you only have 2 million gold and 2 million elixir. You attempt to purchase it with elixir and you get a popup, would you like to use (??) gems or an additional 1 million gold to purchase. You would select what ever method you would like to complete the upgrade. This would make the wall upgrading rind a bit easier for everyone. Clash on!

...thus allowing people to keep their available loot as low as possible. IMO not good for the economy.

Way too complicated. Keep it simple, the way it is currently.

Bring back the upgrade walls with elixer