Here are a set of example Relevant Background and Future Goals and Graduate Research Plan statements for the NSF GRFP in Ecology and Evolutionary Biology.
For ease of browsing you can access all of these proposals here
Please email or submit a pull request if you would like to add your statements to this repo. Please send files as pdf, with as much information as you are comfortable including in the title, such as .pdf, where is RBFG (Relevant Background and Future Goals), GRP (Graduate Research Plan), or Reviews (share if you like). This is a blatant rip-off of Jeff Ross-Ibarra's repo for job materials link
Many resources exist for guidance in writing a GRFP (see collected advice from Jennifer Wang, and Alex Lang, and proposals collected by Alex Lang (mostly in chemistry/engineering).
A 2 min internet search does not reveal many people interested in ecology and evolution, but my guess is that the models are similar across fields. Send links please!