hi, i think that the design of a bearing is really very simple, but actually *making* one needs a great deal of precision.
Not a drawing, sorry, just a basic sketch of a pretty typical layout of Scheu/Teres type, which is really a variation on the ancient Garrard/Thorens design.
The large bearing surface provides some oil drag with a ball bearing/thrust pad at the bottom. An oil reservoir at the bottom, too.
Its sucess depends largely upon the quality and finish of the machining so if I were making one I would make the bottom removable, like the Garrard 401, simply because it's easier to lap a through hole than a blind one. I also think that unless you have access to some very good equipment (I don't!) then it will be a case of very carefully lapping the bore against go/no go plugs and then slowly, slowly finishing the shaft to fit.
regards, jeff