I recall two cases reported in bridge magazines where a 4-2 fit was deliberately chosen. one was unsurpringly a strong clob auction where the captain eventually knew everything and could see that the only good slam was a4-2 fit. Iit took place in Curaçao. the other was from the cap gemini invitational where a polish pair deciided for a 4-2 4S contract in some awkward contested auction.