The Paris Review comes through with an excellent inteview (1969) of John Dos Passos.
The always fantastic Virginia Quarterly Review has a fascinating interview (1977) with Gabriel Garcia Marquez.
This is another good Marquez interview (1988) and explains how he came up with the ice at the circus scene.
To even the playing field, I recommend this short but delightful essay on Dos Passos at the Dos Passos Review. It is an essay about an interview with Dos Passos, so it qualifies.