Iskender Savasir wrote:

>I am trying to explore the solo string literature pre- and post- dating
>the Bach solo sonatas- ...

There is a beautiful solo violin sonata in D by Prokofiev.

There is Paganini's Variations on Nel Cor Piu Non Mi Sento, which has
been recorded by at least Leonid Kogan and Vasa Prihoda.

I have music by Paganini which is a duet for _one_ violin, but I don't
know if it's been recorded.

There is also Wieniawski's Ecole Moderne for violin, and although they've
been recorded I don't know if they fall into the category of being etudes
or not.

Also, I think that including the Paganini Caprices on your list requires
the inclusion of caprices by other composers, for example Dont (op.35?)
and Rode.  The works by these two are often used as violin "studies,"
but technically they are named "caprices".

hector aguilar