I'm trying to see it without thinking of reindeer:
It's stately, but also fusty.
"
Rudy" as a nickname feels bratty and sounds a lot like the word rude.
Rudolf Hess was a vile human being.
I just can't get behind it, even if the reindeer connotations did not exist.
Ralph and
Rafael/
Raphael on the other hand, I can get behind.
Other "
Ru" suggestions:
RunarRufusRupertRutgerRuslan
Other "
Dolph" suggestions:
RandolphRodolfo