large scale roman legionair???

Check at Squadron mail order and look up Andrea Miniatures or Pregreso or fine a magazine called figurines. Usually they are list in millimeters.

Airbrush,

54mm figures abound. Probobly enough to make your own legions.
As for larger sized figs, the range narrows a bit but still a good selection:

Andrea : good for 90mm
Jaguar : 200mm
Michael Roberts : they produce a large scale bust of a Roman Soldier
MIG Prod. : Again...another large scale bust (very good)
Verlinden : 120mm
Warriors : Produce some Galdiators
White Models : 90mm
Marco Lucchetti : 90mm
Poste Militaire : 70mm
Pegaso : 90mm

Time Machine Miniatures produces a line of 54mm figs that are those involved in the Teutoburger Wald from both sides. (This is the battle that a couple of legions were slaughtered to a man by the Germans in an ambush)

Hope this helps. I know theres more out there but this is what I had in my references of companies.

Mike

Airbrush;
Verlinden have a selection of Roman fiqures in their 120mm range, plus a Roman Legionary in their 200mm super scale fiqures.

their web site is verlinden-productions.com