Hrm, ok, so there's 2-plus Respighi violin concertos- the unfinished A major, the A minor all'antica and the Gregoriano (P40 1903, unfinished; P75 of 1908, P135 of 1921) (also the Leggenda P036 and Humoreske P045 of 1902 (both pub. by Ricordi), and the Poema autunnale - also not a concerto, in name- of 1925, pub.1926)?
Hrm. Yes, quite a few libraries with the score of the All'antica, but none I can find (using Worldcat, SBN, FLP) have the parts. I assume they're somewhere, though (or could be prepared from the score...)