Ok. Highlanders stupid train of thought.
GAGR is a great community, and doing this shield/cup/trophy on its own would still be a very good thing to do. However, the trophy is about the rugby community as a whole as well, and to go on our own feels somewhat insular to me. Doing crowdfunding would allow a lot of people who aren't part of this community to join along as well. $2000 From 20-50 GAGR members and $2000 from 100+ members of the community at a whole is the same amount of money, but far more inclusive.
In terms of providing tiers and physical rewards and such, the obvious thing to do would be to go for a site that didn't require them, but you could do something.
Specifically, you could create some sort of booklet. Not flashy I know, but still. Say, A5, professionally designed with all the information about a bunch of things. The idea behind the Trophy, both concept and design. The rules for the Trophy. The founding of the NRC, it's spiritual precursor in the ARC, summary of the 2014 season. Who Shaun Mackay is, and why the trophy was named after him. A quick history of GAGR.
2 obvious tiers. Someone who pays more than $x gets a copy of the booklet, and someone who pays more than $y gets their name in the booklet as a significant contributor. With oodles of Good writers on the site, that's plenty of free labour for the writing, so the costs would be for a Designer and some Photo releases, as well as distribution.
As I said, happy to keep it ridiculously simple as well, and just get a few dozen of us to do it, but something to consider.