Schofields do a repro that is not an accurate repro, but is OK.
Klassicfab have started making them but as with most KF bay window stuff, its impossible to get hold of (in my experience) -
http://www.klassicfab.com/index.php?option=com_virtuemart&page=shop.browse&category_id=1146&Itemid=29" onclick="window.open(this.href);return false;
Autocraft keep talking about doing them - I have asked them at Stanford Hall for the last 3 years and they keep saying they are going to do more bay stuff but I guess this years virtual lack of any Bay stuff on their stall tells the story.