He's always got something up his sleeve.
Perhaps he's going to entertain some big swell he wants to get into his net, or some of the foreign princes he's hand-in-glove with.

You never know what Sir Stephen Orme's up to.

Perhaps he's going to stand for the county; if so, he's bound to get in.

He always succeeds, or, if he don't, you don't hear of his failures.

He's the sort of man Disraeli used to write about in his novels.