Even with all the cameras I have, I would have a difficult time selling them.  I do/have given cameras/kits to my oldest daughter.  Even thought I never would, it is always implied that they are on loan and I could get them back any time I wanted, so they are still "mine."  
I try to use all (except the LF) at least some time.  However, the most used are the Fujicas and Yashicas, a Minolta X*-1, and the Weltini and Welti.  The MF Fuji and Welta get used as well.  A 6x9 Zeiss Ikon (non rf), and a Moskva are in the wings, with the Zeiss getting more attention due to its (lack of) weight.
But sell?  I don't know if I could.  I guess I would have to admit to being something of a collector, but it would be a very small collection.