For the Neruda, try the John Wallace T for Trumpeter CD . I have the Wallace edition of the Neruda which I am working on at the moment. Mr Wallace doesn't record exactly what is printed, not sure which came first, recording or edition.
Wynton's recording of the Hindemith is also pretty good too (maybe some tuning issues.. probably the "focused" sound of the Monette C he used...
) The CD On the Twentieth Centry also includes other standard rep such as the Honegger Intrada, Tomasi Tryptyque, Stevens Sonata , Enesco Legende and Bozza Rustiques. Well worth it!