Well single binary would be nice, but I don't mind compiling multiple binaries. The important thing is that I want a single codebase, and that I am writing it in an easy-to-use rapid development environment (why I am trying to pick Perl/Tk). I have minimal time to spend on this side project, so every minute of my development time is at a premium.

The requirements of the actual project should really be handled by a web server/browser/HTML/CSS/Javascript, but even the minimal stuff I want to do in terms of text editing/diffing and displaying a simple tree of data are way too hard for the browser implementation of CSS/HTML to handle in a way that is consistent across platforms - and believe me I tried. Browser support for CSS 2.1 is about an inconsistent 50%.

Plus I enjoy writing code in Perl/Tk. I'll give PAR a shot.