I mount my projector high on the back wall on a shelf at the back of the room. I use the metal double hook style shelf brackets and double track metal supports screwed into the wall (Something similar to the picture at the link), with a piece of 3/4" wood oak veneer plywood screwed to the brackets. These types of brackets are quite heavy duty and come up to 24" long. (As an aside in a previous home theatre I also put my A/V components on shelves mounted below the projector and onto the same wall shelf uprights. A piece of thin veneer plywood the width and height of the space between uprights on 3/4" shim material between the uprights allowed me to run wires out of sight)

Depending on whether you can mount your new projector upright (i.e. if you have lens shift) or not, you can either sit it on the shelf (which is readily adjustable for height) or attach it inverted to the shelf using a suitable metal or plywood adapter plate (1/8" bolts up through the adapter plate to attache to the shelf above, and bolts down through the adapter plate into the mounting holes on the projector).

If throw distance limitations prevent back wall mounting, either buy a universal ceiling mount, or build a larger shelf and mount on ropes (as you did before) or for something more stable consider using 4 long threaded rods bolted through a suitable sized 3/4" plywood shelf and held with nuts and washers and to the ceiling via a matching plywood plate bolted (lag bolts) into the ceiling joists. Then paint the wood shelf and top plate white.