Custom made bearing for lathes

Hello,

I wonder if it is possible to built with hobby machines a lathe air
spindle or a fluid spindle for a lathe. I am interested in this
because of the very high truth of running of these bearings (
especially air spindle / bearings ). I don't want the lathe spindle to
run at high rpm ( 4000 - 5000 rpm would be the maximum ).
I know most of the air spindle tools are tiny and dedicated to small
and precision works, I guess a lathe chuck would be to0 heavy / big
for this?
Has anyone tried this thing? What would be the cost / effort to do this?