Jon
I happened to be reading my copy of Wargames Ilustrated March 04 No.198 which has an article by Michael Sayce on Rivoli with OB (part of a series on the Italian battles of Napoleon-an interesting series of articles).
The author says orbats are difficult to track down and there seem to be gaps. Not my period but here it is for what its worth:
French
Commander: General de Division Bonaparte
(18,000 inf 4,000 cav. 60 guns)
General de division Massena
32e Demi-Brigade de Ligne(DBdeLi) ??
General de Brigade??
19e, 93e DBdeLi
Genral de Brigade Leclerc(cavalry)
25e ChaCh15e Dragoons
General de Division Rey
57e DB deLi, ??
General de Brigade Brune
75e DBdeLi,??
General de Division Joubert (10,000)
Genral de Brigade Vial
4e and 17e DBdeLi
General de Bridage Santos
14 and 85e DBdeLi
Austrians
Commander Feldzugmarschall Baron von Alvintzy (28,000,90 guns)
Brigade Commanders:
GM Lusignan (4,000) GM Liptay (4,000) GM Koblos(5,000) GM Ocksay(5.000) GM Quasdanovitch (7,000) and GM Wukassovitch (4,000)
Infantry
Hoch und Deutschmeister IR Nr.4 (3 battalions)
Huff IR Nr.8 (3rd Battalion)
M Wallis IR Nr.11 (3rd Battalion)
Reisky IR Nr.13 (3 companies)
Klebek IR no.14 (2 Battalions)
Preiss IR Nr.24 (3 Battalions)
BrechainvilleIR Nr.25 (1 Batt)
Strassoldo IR Nr.27(1 Batt)
Nadasdy IR Nr.39(3 Batt)
Erbach IR N r.42 (2 Batt)
Callenberg IR Nr.54 (1 Batt)
Khevenhuller Grenadier Regiment
Banater Grenz In. regiment (GRIR)(2nd Batt)
Karlstadt GRIR (4th,5th,7th and 9th Batt)
Banalisten GRIR (5th Batt)
Wallachen GRIR (2nd and 3rd Batt)
Freikorps Gyulai (2 Batt)
JagerKorps (1 Batt)
Cavalry
Wurmser Hussar regimnet Nr.30 (2 Squadrons)
Stabs Dragoon Regiment (2 Squadrons)