Well, the best English equivalent to the Ring poem would be the "Story of Sigurd the Volsung", by William Morris -- a versified version of the tale, in which Sigurd acquires some definitely Socialist tendencies but is otherwise fairly close to the Volsungasaga sources, with some synthesis and gloss not unlike Wagner's, and a fairly muted use of archaic language (as compared to Wagner's extraordinary vocabulary). It is much more an independent work of fiction than Morris's straight translations of the Volsungasaga et al. They have generally survived, if only as secondary sources alongside modern versions, where the poem, whose sensbilities are distinctly Edwardian, has been relegated to the back shelves. So, probably would Wagner's, and the definitive treatments of the legends would be those of he playwright Hebble, and perhaps also Ibsen's The Vikings at Helgoland.
Cheers,
Mike
'