Anton Rubinstein Early piano concertos

[giles.enders]

There were three early piano concertos by Rubinstein written in 1847, 1849 and 1850.  The second was in E minor and the third in C.  In 1856 he reworked the third as a piano octet in D Op.9.  Does any one happen to know about the fate of the manuscripts or if the concertos were ever performed? 

[eschiss1]

Taylor has a few things to say about them in "Anton Rubinstein: A Life in Music", noting a performance of the C major in 1849 (28 February OS/12 March NS) (Vieuxtemps conducting), and believes that the F major was probably in a suitcase of Rubinstein's that was confiscated and so has disappeared...

I wonder if it's possible that the F major concerto Op.35 (composed in 1851??) was an attempt to reconstruct the 1847 concerto...

Also, Taylor describes the 3rd "lost" work, the one that does survive in the sense that he reconfigured it into the octet, as a D minor concerto, not a C major concerto (is the Octet primarily a major-mode work or a minor- mode one? If not, the latter statement may not make much sense...