dear Eleanor
sorry.  The Cahsneo vector you refer to is only fleetingly described in the
article:
Pirrotta, V.  (1988)  Vectors for P-mediated transformation in Drosophila.
In: Vectors.  A survey of molecular cloning vectors and their uses.  Eds.
R.L. Rodriguez and D.T. Denhardt.  Butterworths.  Boston.  pp. 437-456.
The brief description of Cahsneo and some vectors based on it are on p. 445
and p. 448.  The Cahsneo with hs43-lacZ is described (also sketchily) in:
Qian, S., Varjavand, B. and Pirrotta, V.  (1992)  Molecular analysis of the
zeste-white interaction reveals a promoter-proximal element essential for
distant enhancer-promoter interaction.  Genetics  131:79-90 
It contains not the full hsp70 promoter but just the TATA box, with
sequences upstream of -43 deleted.
The article in the Vectors book describes the cosPneo vector but concerning
the cosPer vector, it says only that a cosmid version of CaSpeR is also
available (cosPer).  I am afraid that it has never been described any
better than that.  However, what it amounts to is just the cosPneo with the
hsp70-neo gene replaced by the same mini-white gene that is present in
CaSpeR.
Sorry about this inadequate answer but the details have never been
published.  Journals do not like to publish papers on such thing these
days.  And rightly so.  But there is no other institutionalized way to make
the information accessible and quotable.
V. Pirrotta
Dept. of Zoology, Sciences 3
University of Geneva
30, quai E. Ansermet
CH-1211 Geneva, Switzerland