http://wasmer.io is now released as version 1.0 stable. It’s written in Rust and would make a nice addition to the Redox ecosystem once Redox is completed. The advantages are that different processors and OS architectures are possible to implement code in so that tightly implemented architectures like Haiku and Redox can start to edge out the mainstream bloated operating systems. It even has its own package management system. The only part written in C++ is LLVM for the final compiles.
What Wasmer lacks is a full-featured runtime environment. It is currently only for edge servers and command-line utilities due to it lacking proper graphics, sound and GUI routines. Is there a possibility that a media-aware OS can make up the difference?