I seriously doubt it, given the tendency for _all_ ships in Babylon 5 to have sizes that seem to ... well, let's just say that the sizes for all ships in Babylon 5 tend to change to meet the needs of the story at the time, and the whims of the special effects guys.
I do remember from the Technomage books they can have atleast 2-5 passingers if i remember correctely that elron did have atleast two passangers which would mean they have a small amount of extra space beyond the pilot
Well I'm guessing from what I can see of my taped episodes of Crusade that the ship is about the size of the Earth Alliance Light Shuttle or perhaps slightly smaller (from what I can tell the shuttle is about the size of a large leer jet which would place it around 30 meters or so in length,again I'm guessing there). The larger inside than out is just an illusion,they are designed mostly,from what I can gather,for speed and stealth (to get the mage around space when needed,and to do so as fast as possible so they could get back to their places of power) and thus were not large. If anyone has better or more accurate information than that by all means say so