Ehwald favoured quod (KB 48), but all except one of the passages he cited are instances of quod superest or quod reliquum est.
All six instances of the idiom cited by the OLD (quod 6c) are from poetry.
Artificum dies (quod Minervae) aedis in Aventino eo die est (dedicata).
Than quod he: by my iudgmente, he that ought the shetes shulde haue the rynge.
I quote the passage: 'Egnatii autem Metelli longe minori de caussa; qui uxorem, quod vinum bibisset, fuste percussam interemit.
Than (quod the frere to the gentylman), ye are the more fole to aske for hym.
"Trahit autem magnes ferrum ad se, quod ferro sit ordine superior apud vrsum" (p. 287).
Nay, quod the herdman, I wyll not tech you my connynge for nought.
No, by the masse, quod he, thou were on the pyllorie the whyle.
quod the executours: thou shalt haue a peny, for thou saist trouth.
[1700+; perhaps fr quadrangle; perhaps fr Romany quaid, ''prison'']