Rana can mine a vanity npub for you.
https://github.com/grunch/rana

The author of Rana is self-admittedly not an expert in cryptography but claims that the GPU is not as efficient in calculating elliptic curve keys.
https://github.com/grunch/rana/issues/31#issuecomment-1428147938 

 Thanks, I'm using Rana right now. Glad to know it's been addressed at least.