Since vanguard isn't selling aquamarine name tapes where should I buy them?
If you're buying tapes you should just switch to dark blue.
+1 - You won't be able to get grade insignia, badges, or anything else in ultramarine from VG anymore,
so just getting tapes from various other sources Google can provide isn't going to help you much.
I'm not running out and changing mine, but anything new I bought today would get the dark blue.
The fact that they look so much better is just a value-add.