Dunno, it depends on whether you believe Lacy was any good to begin with or if Joe just completely ruined him. Give his run after Joe, it's points to the fact that he really wasn't world class, the calibre of fighters he's lost too are terrible
Lacy had some wins over good fighters like Vanderpool, Reid, Sheika, Tsypko, Manfredo. He never had a huge win but he was a good fighter and there is no denying that. He is like Brett Rogers in MMA, undefeated fighter who ran into a great and got ruined. Fedor ruined Rogers. Calzaghe ruined Lacy. To answer your question, I think Cloud would win a late stoppage slugfest.
Lacy. and by KO, late. Lacy had a lot more to his game than Cloud did. he actually had some good boxing ability, but fell in love with his KO power and strength. Cloud would be a style that would suit Lacy down to the ground. he'd be at full affect there. he's also much better at fighting on the inside. so yeah, Lacy. and with confidence.