Thanks for all your ideas.
Yes there are heaps of trio sonatas that I have found but of course they are all Baroque, and I was actually hoping to find something Romantic or 20th/21st century if possible!
Yes the Bach Double is a great piece! But my sister (piano) and me (violin) learnt it with various other people about 5 years ago and we're hoping to find something new to do now that we are doing the 2-violins-and-piano instrument combination again (for a few years we did piano trios and some piano-clarinet-and-violin trios).
And the Shostakovich are violin duos/duets (whatever you like to call them), so the piano part is only really an accompaniment...
Argh!! It is proving more difficult to find suitable music than i thought it would be...