Yikes. One would think that could be pared down by a significant amount: Node is only ~40mb installed, and the various webkit browsers aren't much bigger than that.
See my other comment about implementations' core image sizes. SBCL is the worst offender for runtime space overhead[1], and it's CLOS implementation is heavily biased towards the "space" side of the time/space tradeoff, and a brief look at the implementation of this shows a lot of CLOS usage. I would expect that delivering with a different implementation would show a significant reduction in size.
Barring that, most GUI executables are fairly insensitive to startup time, so SBCL core compression would the lisp image down by a factor of 4:1.
Lastly, you can always just not worry about it:
du -s /Applications/*.app | sh ~/avg.sh
Total: 28529040; Count: 126; Mean: 226420; Median: 56752; Min: 8; Max: 6132408
1: Note that SBCL generates the best code of any Free lisp implementation, and makes it the easiest to tune your code for better performance. As disk space is cheap, it's what I use for most of my applications.
