There's plenty about t-p, although I wouldn't say anything first rate.
The Hindemith Sonata is quite good - it has an absolute beast of a piano part and ends with a 'Swashbuckler's Song'
Welcome Not B - for a start I think baritone horns + Ufos has some mileage left so we look forward to your future posts !
As for trombone + piano, I reckon the piano part of the Hindemith's not nearly as beastly as you make out. I'll deal with that any day in preference to the last couple of pages of the tuba sonata.
And I'd nominate the Frank Martin Ballade as first rate !