Don't get rid of the 138S. Get a larger camera.
I use a Saunders 4550XLG/VCCE enlarger for 4x5", 6x7cm and 35mm.
I use the 138S for 8x10" enlarging and 7x17" contact printing. See my gallery for two shots of the 138S with an Aristo 12x12 cold light head and 8x10 negative holder.