Your use case might be a fit for the modular server implementation you see in my footer.
Lets discuss what you need, so I create support for.
BTW: Running the bitsofproof server gives you a normalized relational dstabase of the blockchain, sobalances can be queried via SQL. I also consider to add pruned view of unspent output.
This looks promising. I will starts an EC2 instance later and try to get it running.
I am crazy busy at work right now so it may take me to the weekend to try this out.