Regarding DescribeLoadBalancers, are you certain of that behavior? The documentation suggests otherwise, by default:
Returns detailed configuration information for all the load balancers created for the account.
If you specify the load balancers name, the returned results should be limited to those sets of load balancers that you specified:
If you specify load balancer names, the action returns configuration information of the specified load balancers.
Here's a link for the related documentation in AWS SDK for iOS 7.1, if you're interested. It seems to me that this should work fine if you simply do not request any specific ELB names.