Ah, if only some fate could swiftly come— not a painful one, nor one that left us long bedridden—that would bring us eternal, unending sleep..."Some fate" in English, but in the Greek 13 words separate τίς from μοῖρα, a good example of hyperbaton.
φεῦ, τίς ἂν ἐν τάχει μὴ περιώδυνος
μηδὲ δεμνιοτήρης
μόλοι τὸν αἰεὶ φέρουσ᾿ ἂν ἡμῖν 1450
μοῖρ᾿ ἀτέλευτον ὕπνον...
I don't have access to A.M. Devine and Laurence D. Stephens, Discontinuous Syntax: Hyperbaton in Greek (New York: Oxford University Press, 1999).
From Kevin Muse:
Literally τίς is an interrogative adjective, modifying, as you say, μοῖρα, the whole thing being a question with a potential optative—"What fate might/ could come....?" But the upshot is that it is a wishful thought, and so the translators opt to translate τίς as indefinite, though it is accented and not enclitic, and they render the optative as one of wish. I see that Smyth cites this passage as an example of a potential optative used to express a wish at § 1832.