Proper actions on finite products of quasi-trees

We say that a finitely generated group G has property (QT) if it acts isometrically on a finite product of quasi-trees so that orbit maps are quasi-isometric embeddings. A quasi-tree is a connected graph with path metric quasi-isometric to a tree, and product spaces are equipped with the ℓ 1 -metric. We prove that residually finite hyperbolic groups and mapping class groups have (QT).