shelf-like list?

[kj]

I'm looking for a module that implements "persistent lists": objects
that behave like lists except that all their elements are stored
on disk.  IOW, the equivalent of "shelves", but for lists rather
than a dictionaries.

Does anyone know of such a module? 

(I suppose that I could slap together a crude implementation of
such a thing by wrapping a shelf with suitable methods to simulate
the list interface.  But I'd rather not roll my own if a tested
implementation already exist.)

TIA!

~K