I think the last Tsarina
Alexandra was nicknamed
Sunny. But don't take my word on that.
I think 'wordy' nicknames like
Sunny, Peanut, or whatever come naturally from any name. It could be
Isabel Rachel '
Sunny' for all I cared, I wouldn't ask questions.
As for a full name, you could pull it off with the right attitude. Some might comment on it as cheesy and isnt to everyone's tastes but it is do-able.