Jace,You have some decisions to make. Let's start with what region you are from and are representing. A Burgundian Ordinance could have had individuals from a number of different regions. Northern Europe (Lowlands), western (modern France), various regions of western Germany (or Switzerland), or Italy. The answer or guidance to your question as to what crossbow from a military portrayal is going to depend on how or where you received the weapon.
There are many styles of crossbow from this time period. Northern (flemish), western, central and southern German with certain variations further. Additionally, how you use the crossbow would change certain details. A mounted crossbowman would not likely have the same style or length of crossbow as a foot soldier, for example. The bridle would be different. How do you intend to "load" the crossbow? Strap hook? Crannequin? This changes it too. As you can see, there are a number of decisions to make, starting with your portrayal. Did you receive the crossbow from Burgundian Ordinance stores? Or did you purchase it as part of your required equipment to enter service before you left home?
I think the best research book which, unfortunately is out of print and hard to come by, is "Die Armbrust" by Egon Harmuth. It is in german and has some of the best detailing research of extant crossbows.
Are there crossbow makers? Yes. You get what you pay for and how much detail is up to you. And, what are you going to use it for? Rapid target shooting, or do you intend to have it for show and be able to punch holes through modern armour?
Some examples of the styles are here: http://www.crossbows.net
Other details include what type of wood, etc., but I won't go into that here.
Back to your original question of wood vs metal. Many had metal bow arms at this time but certainly not all. It depended on the where and when. The problem with metal is that early metal fractured easy and was particularly susceptible from severe cold. However, from a modern point of view, a metal bow arm would be easier to make, control it's stiffness and power, and is easily replaceable.
Happy researching!
PS. Don't forget about the new crossbow laws you have to contend with.
[ 11-30-2004: Message edited by: Friedrich ]