Yes, it actually is possible. I stumbled upon this a while back and thought it was a pretty nice usecase.

Here's the thread: https://bitcointalk.org/index.php?topic=1231148.msg12830232#msg12830232.

We simplified and expanded on it afterwards in another discussion, I was the OP IIRC. The simplified scripting would be something like

pub_key OP_CHECKSIG
OP_IF (num of sig required) pub_key1 pub_key2 (total pubkeys) OP_CHECKMULTISIG
OP_ENDIF
OP_VERIFY