We discussed your idea but don't suppose we will be able to provide a pre-release version of the Developer Manual at this point. We believe we'll have the manual ready in about 10 days' time (or less), so it won't be a long wait.
There is still a lot of stuff that needs to be edited/rewritten and we think incorrect documentation might create more problems than it solves.
Please accept our apologies for not being able to comply with your request and do let us know if we can help you with anything.
All the best,
the Telerik team