Standing at roughly 6 feet, Balthier is easily one of the tallest characters in your party, if it weren't for his femal counterpart, Fran, who is taller than him by only a few centimeters. He has a fairly strong build; he is able to lift Vaan over his shoulder with only a little difficulty, and consquently, throw him off a tower only to catch him moments after doing so. His in-game motion actor, Sean Ryan, is of western decent, which is who Balthier's physique may also be based on. His hair is undoubtedly a warm, light shade of brown, but the color of his eyes are of a different matter. In drawings done by Akihiko Yoshida, the character designer for Final Fantasy XII, he is shown with eyes that are of a light blue, but in most artworks and in FMVs, they almost tawny. In Itadaki Street Special art, his eyes are in a grey shade.
On the collector's edition DVD that came with the North American release, Akihiko Yoshida stated that his clothing designs are inspired specifically from attire from different time periods in histrory. When looking at several deisgn elements, the staff has stated that much of their influence comes from Ancient Rome, and periods in areas where alchemy flourished; they even cited the popular anime adaption of Full Metail Alchemist, a project that was being worked on by Square-Enix at the time the game was being developed. While the latter is questionable on whether or not that was implemented into character design attributes, the former certainly is. Balthier's attire is a mix of Ancient Roman, Medival, Victorian and possibly a hint of Renaissance, all with a modern flare. The golden, intricate patterns sewn onto his vest, for example, show patterns common in upper-class Renaissance or Medival clothing. While his pants are always the butt-end of any Balthier joke, it functions both as rather stylish and sturdy material for his rugged travels.
With a little research, I did find that his shoes are similar to a kind of Ancient Roman footware: calcei repandi. Calcei repandi are characterized by having a closed-toe that is slightly curved upwards. The only difference been Balthier's shoes and an actual one is that his are laced up in the back; however, laces are also a characteristic of several Roman sandals. In Rome, only citizens of high roman status were entitled to wear calcei repandi. Balthier isn't the only character whose footwear are influenced by Ancient Rome; Basch's shoes are similar to that of cothurni, a type of hunting boots that lace up in the front.
At a press conference interview, Akihiko was asked whether or not if the work of Nomura Tetsuya, a popular character designer for several other Final Fantasies, etc., was an influence in his character. He does not deny this, specifically stating that bright colors are the key. Although Balthier's clothing doesn't have any kind colors that stand out, he does own a set of colorful rings and bracelets.
If there were some kind of design element of Balthier that was inspired by Nomura, it could possibly be the belts! First seen on Final Fantasy VIII's Squall Leonhart, Balthier wears a similar style with belts where the two would cross over each other, forming a type of "X". However, unlike Squall, Balthier's belts stay in place by two pouches that hang on each side, acting as weights. (I think we've found a character designer who understands the laws of physics!)
Lastly, In an interview with IGN.com, Akihiko expressed his personal input on our favorite dashing lead man! The following is an excerpt:
IGN: Who is your favorite character in the FF12 line-up? Does that character share any commonalities with any key characters in any of the other games you've made?
Akihiko Yoshida: My favorite character is Balthier. But he is a completely original character. He's not based on any other character from projects he's worked on before. He's based on someone I admire and he plays a very important roll in the story.