Parece algo complicado, según lo que encontré:

<<If A grants a tenancy to B

·B then grants a tenancy to C

·C then grants a tenancy to D

We then have the position where:

·A is the head landlord and also the superior landlord to B, C and D.

·B is the superior landlord to C and D and also a mesne landlord.

·C is the superior landlord to D and also a mesne landlord.

·A is B's immediate landlord, B is C's immediate landlord and C is D's immediate landlord.

·B is a tenant and C and D are undertenants or sub-tenants. D may also be referred to as a sub-undertenant.>> (y sigue)
http://www.landlordzone.co.uk/forums/showthread.php?15390-Ca...

Parece ser algo como "arrendador original":

http://ius.scjn.gob.mx/documentos/tesis/214/214206.pdf

http://books.google.com.ar/books?id=bY4BKHJms0sC&pg=PA174&lp...

Ej.:
Los bienes inmuebles que es independiente de cualquier propietario superior.
http://centrodeartigos.com/articulos-informativos/article_72...

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Note added at 1 hr (2013-06-24 18:56:34 GMT)
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Bueno, el enlace que he puesto no es el mejor ejemplo, pero "propietario superior" se usa en este sentido.
Este enlace es un poquito mejor:
http://books.google.com/books?id=q-nRvMVQGLsC&pg=RA1-PA64&lp...

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Note added at 2 hrs (2013-06-24 19:08:37 GMT)
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Superior Landlord means the person for the time being who owns the interest in the Premises which gives him the right to possession of the Premises at the end of the Landlord's lease of the Premises.
http://www.linleyandsimpson.co.uk/index.php?page=jargon_bust...