Im rewiring the attic my ceiling joist are 2by4 do they sell housing for those joist

My guess is that you have pre-engineered wood truss that is 2x4, but you should have plenty of room above.

If there is no room but the 4", then no there is no recess housing for this. Except maybe for some high end halogen or CMH lamps, both very expensive.

If there is room, use an IC rated recess housing, and push the insulation away just enough to fit the housing.