Coming in October from Naxos:
KLENGEL, J: Concertinos for Cello and Piano (Complete):
Cello Concertino No. 1 in C Major, Op. 7
Cello Concertino No. 2 in G Major, Op. 41
Cello Concertino No. 3 in A Minor, Op. 46
Concert Piece in D Minor, Op. 10
Martin Rummel (cello), Mari Kato (piano)
8.573793
Thanks, Mike. The details at Naxos' website read as follows:
Based in Leipzig with a length career as principal cellist of the Gewandhaus Orchestra, Julius Klengel was a renowned soloist and revered the world over as a great interpreter and pedagogue, whose works are still in use by students today. Composed in true Romantic style, the three Concertinos were written for teaching purposes, the first coming closes to the idea of a mini-concerto but all having virtuoso elements and expressive and lyrical central movements. The Konzertstuck, Op. 10 gives the piano equal status with the cello to create a thrilling conclusion to any programme.
https://naxosdirect.com/items/klengel-complete-cello-concertinos-417881 (https://naxosdirect.com/items/klengel-complete-cello-concertinos-417881)
So, no orchestra involved!
Were these ever orchestrated?
Maybe by someone. Not to my knowledge though?
A quick snooping around in youtube shows that somebody did in fact orchestrate at any rate the C Major concertino. E.g. here (https://www.youtube.com/watch?v=eDT_5QXwBA4), here (https://www.youtube.com/watch?v=30A3Hmoy0bg) and here (https://www.youtube.com/watch?v=aGJg_gfCjVg).
All of these are amateur performances. Nonetheless they show that the piece rather gains from the orchestration.