I know, that this answer is quite "too late", but I recently tried to build a simple gui for linux. With JAVA and the less.js it is not just linux, but cross-platform.
Simpless isn't supported anymore (since 1.3 as written in their blog) and Crunch uses Adobe Air which is also out of date.
here is my project: http://project.splashfish.de/Le-css/
