To address your questions:
1) You should wait for this week's build;
2) You are right, we do not support CDN for the internal builds. The reason, apart from the official company policy not to do so, is for the life span of these builds -- each build supersedes the previous. You could, however, reference statically a previous official CDN, provided that there are no changes in the CSS / JS / images, which is highly unlikely.
Also, internal builds have not passed proper QA testing. True, they pass all the automated tests, which guarantees integrity and somewhat correctness of the code, but nothing can replace proper human tests with an eye on the detail.
This is why we generally do not recommend the use of internal builds, except in the cases of development and a development halting bug being fixed in that particular internal build.
3) Internal builds are like regular builds in terms of limitation -- available both in trial and dev version. That said, apart from the CDN features.
4) In order to address your next question (and many similar for that matter) we have the Beta releases. They do have CDN support and have most features a Q release will have. They are generally a preview of what's coming next and ideally, the difference between a Beta and a Q release would be minor bug fixes.
That said, a Beta should be out next week.
the Telerik team
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