That was sort of how it went with the mobile home idea, thinking we may need to do a lot of "updating" at at some point decided building could be cheaper - as we do all our own labor.
We've put up plenty of pole buildings, and don't want to go that route. For DIY, a small framed structure is easier to build. DH already has his 30x40 shop, and two machine storage sheds, the converted pig shed that has the boat, and the converted grainery. Since we've not used the boat in years, if we sell it he'll have a lot more room for his "stuff".
I have the long garden/storage shed. Most of the storage shed is full of my furniture I moved out of the house to make room for sewing stuff, so that will come back in the house and DH can have that building too. That is the one with the newer floor, so maybe next year we'll take the building down and rebuilt a nicer one on top of the foundation. Some of the older buildings are in very poor shape - and nothing special so I won't feel bad about rebuilding them.