That's a tricky one - the bench needs to be strong, stable and vibration free. I once came across a web site where a turner had produced his own lathe bench, and filled the bench itself with sand in order to make it stable. I guess you lose the storage space, but he reckoned that it was rock-solid. Unfortunately I can't remember the URL
It is important that the height of the axis between the lathe centres is at the height of your elbow when standing naturally upright - it's useful to have somebody else measure this. If you try to do it yourself it is difficult to avoid bending and lowering your elbow.
Because I am tall the bench produced for my lathe was of insufficient height so I decided to make my own. I built two 18" square pillars, from standard concrete blocks, for the ends of the lathe bed to rest on. I topped across this with a board of 1" (or the equivalent in metric!) MDF and then bolted the lathe ends down through the MDF into the concrete pillars. Care when building the pillars to the designed height resulted in the lathe axis being just right. The space between the pillars was used for a useful cupboard, with the cupboard base set about 6" above the floor (for feet space). It has proved excellent, with nil vibration, and cost about 30 quid all-in - compared with £100 for the proprietory stand for my lathe.
Built my own - 2 A-frames joined by a shelf near the bottom and a 10x4" piece of old pine at the top. The back is 1" MDF to add weight and rigidity. The front is open, to allow placement of the (6x25kg) sacks of sand and for use as a foot rest/storage space. The lathe is just bolted through the top.
It's blinking heavy without the sand, so I can move it, and with the sand it's even better. More sand would be even more solid.