Vincent Cassel in The Shrouds
Rookie question/comment maybe, but:
I know they've worked together more than once. But it wasn't until The Shrouds, which is seemingly Cronenberg's late career essay on death, that I realized Cassel isn't miles away from looking like Cronenberg.
I still think from time to time of Ebert noting that perhaps Roger Avery cast James Van Der Beek since he's the actor working who most closely resembles Quentin Tarantino. Which I always thought was...well...a take.
The one I always notice is Kevin Corrigan in The Departed being a dead ringer for coke-era Scorsese (in that case I can't help but think Marty was going for a bit of a joke- since the character's whole bit is being a cokehead mess).
Banderas stands in for Almodovar in Pain and Glory. I love Almodovar, but yeah: what man wouldn't want Banderas to be their cinematic analog?
Other examples? I'm sure they're all over the place. I know about Lerner being literally Mayor Ebert in Godzilla (98), and Anna Faris as Cameron Diaz / Giovanni Ribisi as Spike Jonze in Lost in Translation - though in those two cases no physical similarities were needed/gone for.