If you call around to your local formalwear rental places, ask if they have "waist jackets". I got one of these...they just sold it to me as ex-hire...and it's not bad. You may want to ask if they have a three button vest that'll go with it.

The one I found is from the "Robert Wagner Collection" and I expect that it was left over from the late seventies-early eighties.

Best

AA