I'm the co-founder of Trestle (Brian), and this is something that my partner Sham and I struggled with as well as we both have created apps that relied heavily on a server backend.
With the Chain Server you basically bundle your API calls into "chains" that you then send over to the server in 1 shot - it's actually really slick. Of course not all API calls can be bundled this way since they are more of a "one shot" type call, but if you want to store images, audio, user info, objects, etc. and those items have relationships, you can do it all in one round trip. Our clients make it super easy to make a chain and execute it too.
We're looking for developer feedback, so please let me know if you have any suggestions or questions - we're all ears. Thanks!