I like the mahseer recommendation. Giant danios would be fine in that temp range. They actually take pretty cool temps fine. Albino channel cats are another option. I know they are small, but if you have ever seen a school of 300-500 albino cories that is pretty cool. They will be fine at those temps, I used to bring them from 72 down to 65 to get them to spawn. I also liked the big gar option.
Gold tinfoil barbs would look great from above and I have seen them take pretty low temps. Roseline sharks are another great schooling option. Red glass barbs could be cool in a large school.
Someone mentioned cool water cichlids. Gymnogeos would love that set up, but usually cichlids don't look great from above. I personally like the hi fin banded loaches. They get huge and go through some cool color changes. Even better would be Leptobotia elongatata. That is an amazing loach that goes through pretty big temp swings. The gold dojo is an interesting idea as well. They get bigger than many people realize (though still not huge).
Rainbows are an option. Seriously fish claims turquoise can take down to 68F. If that is true then it is an awesome fish. I had them in a tank I had to look at from above and they were beautiful. They would flash that yellow streak down their head in the mornings and it was great. I never pushed them that cold though for any extended period of time though.
The fact is you have room to make this a pretty awesome community. Have fun and figure out what you like. Your temp range isn't as restrictive as you think. The biggest thing to remember is that the fish need to look good from above. That is why you see so many albinos in my suggestions.