Piggybacking off Ticken's idea for a moment, here's what I think would be a bit more appropriate if an animated alumnus trophy were to be used (I get that this is probably too fast, it runs at the same speed as top badges but maybe I could do with making certain frames last a bit longer while keeping the overall time the same):
I think the flashier version Ticken showed is just a little too much for an alumnus trophy and kind of takes away from the current trophy. Upon asking a few people they said it -still- takes away from the current trophy which I get, so I mocked up a (very poor) version of what would effectively be a "Top" version of the SPL trophy.
Has a small shine (it can be made bigger if required), gives it a little more prestige, but upon asking around ABR brought up the point that messing with the SPL trophy that's been around for eons at this stage is something that might be unpopular, which is fair enough.
What surprised me most, though, is that I didn't see a single option that just involves using a purely greyer version of the current trophy.
Just two examples taken from the frames of the gif I posted above. Earthworm and Raiza both posted something similar but they had their own issues with visual fidelity / ability to tell at a glance which is alumn and which isn't, but I feel like this makes for a stark enough difference that that isn't an issue:
If you're worried about it not being super noticeable you can even change the border colour of the current trophy like Tony suggested - I don't really like the gold myself but it does certainly make it stand out.
Ideas I don't like are changing the background colour of the trophies, it looks a bit too tacky for my tastes. I didn't bother w/ the Snake/WCOP trophy for this example but if people like these I can mock those up - we could also consider giving each circuit its own colour if we want to apply this to those as well. Completely agreed that all alumnus trophies should be separate, people who won SPL 3 times should have 3 SPL Alumnus trophies. Here's an example of how it might look if I were good at mons:
Personally think it still looks nicer without the gold, the contrast isn't particularly nice, but maybe there's a better midground colour? And just for fun with the gifs:
Would be happy to know what people think of this and I'd be good with adjusting it if anyone wants to see what a specific thing would look like, my spriting skills are certainly not amazing but I think we can make something great here.
edit: it has been brought to my attention that i am in fact a dummy and that 2x spl winners would still probably only have one alumnus trophy. that's fine tho same principal still applies, just pretend there's only one alumn in my screenshots above
Edit #2: after talking with
Boat, we also came to the conclusion that a trophy that uses two cycles of a standard top badge (i.e. 22 frames) might look better. Here's the result of that: