NOT A TEACHER
Great question, Goldfish.
I have found some information that may interest you and other learners.
1. "Fool that he was, he managed to evade [escape] his pursuers [people chasing him]."
a. According to four scholars, that is a very elegant way to say, "Even though he was a fool, he managed to evade his pursuers."
2. Another scholar gives this sentence: "Idiot that I am, I forgot the tickets!"
a. The scholar says that this word order is "sometimes used in clauses of cause."
He does not tell us what that sentence means, but I have read that in such sentences, the relative pronoun "that" is being used as a conjunction. Something like the word "as (because)":
So that sentence probably means something like: "As I am (an) idiot, I forgot the tickets."
Credit: Those four scholars (Quirk and three others) wrote A Comprehensive Grammar of the English Language (1985 edition), pages 1098 and 1107; the other scholar is Paul Roberts in his Understanding English (1954), page 328.