Nice looking spec. I just tried it in my Firefox 2. Based on the advice there I would expect one of the following two to cause script tags to default to version 1.7 but neither does:

<META http-equiv="Content-Script-Type"
  content="application/javascript;version=1.7">

<META http-equiv="Content-Script-Type"
  content="text/javascript;version=1.7">
[download]

(Either content version will work in a type tag to a script.)

Given that failure, I am not going to rewrite my code sample to be inlined in a script tag. I'm just going to assume that it won't work.