Dumb idea: vanity private keys.
Discussion
Agree. That is pretty dumb 😂
But it could be your little secret! And now the xprv can be used for all different types of address!
Sale: Pre-Used Vanity Private Keys
Lol dumb me 😮💨
what does that mean?
Solo there's a thing called "vanity Bitcoin addresses" back in the day. You can spell some fun words. So like 1Pr01F1C... could be an example.
http://bitcoin.stackexchange.com/questions/20305/ddg#20311
Since those are legacy addresses, they are more expensive to spend from now too (as they take more space on the block chain)