I think there is a confusion here between two concepts:
Recommendation letter
versus
Letter of support
It is perfectly fine to get letters of support from someone that do not know you or your work closely, but have read your project/idea and thinks it has merit for financial or other support.
Concerning the first one, it is absolutely imperative that the person knows the candidate from having worked with him/her for a long period and closely. So, yes, a complete stranger asking for a recommendation letter may be seen very, very negatively and it is embarrassing.
But suppose for a moment that a very "important" researcher accepts to write a recommendation letter to someone he doesn't know. There are only 2 options:
- He/she will lie about the candidate (something very unlikely, sp. from an "authority")
- He/she will be honest that he does not know the candidate -- and therefore it will be a poor rec. letter (even if the project seems very good -- but again this appears not to be important for the job in question)
So you see that is why such a thing is not of usual practice.
Also, I think Marcus is making a confusion here. I think every one is entitled to fight for their ideas and independent research, but there are right and wrong ways to do it. My considerations above are meant to offer him a positive advice.
As a last word, I think it is perfectly fine if he collects letters of support to his project from "important" researchers, if he can, and attach them to the recommendation letters from people that have professionally worked with him. This could make him a good candidate for the job.