Preheat the oven to 375 degrees F. Line a large baking sheet with parchment paper. Combine the first 8 ingredients in a bowl. Spread the vegetables on the baking sheet. Roast for 30 minutes, stirring occasionally, or until tender.
Cut the baguette widthwise into 4 equal pieces. Cut each piece lengthwise in half. Spread the cut sides of the baguette with pesto flavoured mayonnaise. Top the bottom piece of each quarter baguette with baby salad greens, roasted vegetables and goat cheese. Drizzle the vegetables with a little balsamic vinegar, set on the top pieces of baguette, and serve.