Around ´74 Elvis put his own money to help out Arthur Crudup in a project about a record label or a sound studio or something like that, don´t remember well.
Anyway, the proyect for the ELvis Blues Album that never happened was around '72-'74, so just wondering, Imagine a duet of Elvis With Mr Crudup on that one.
About someother material for that one, well, Elvis never recorded anything from The Howlin WOlf or Robert Johnson, so there are some choices; dificult to say which songs would Elvis have choosed from them, probalbly some obscure sides, not song already covered by other artists like The Stones.
He loved Lightin Hopkins so he may record something of him, dont know really, Elvis knowledge of blues was almost as wide as his knoledge of gospel music, so theres a vast amount of artists there, dificult to think what would have been Elvis choices.
I personaly would love to hear: "You don´t Know Me" original by Magic Sam, on Elvis voice; as well as Sonny BOy WIlliamson: "One Way Out".