Hi Hrafn,
I took a look at my notes to see if I could find anything relevant in the compiler/stdlib and nothing came up. Most of the optimizations we can perform we already do so. Maybe you could find something by studying functions in the standard library individually but I cannot think of anything systematic.
However, you may be able to contribute to related projects. For example:
1. ExDoc - we are discussing converting the JavaScript aspects to Elm
2. GenStage + Flow - it would be nice to benchmark solutions written in Flow against solutions in other stacks such as Apache Spark. To be relevant, you would need powerful machines, however.
I am not sure if those fit your criteria.