|The only difference between 'child' patterns and 'toddler' patterns is the length. According to Butterick, it's about one inch. Likewise, if you're making clothes for your toddler from vintage patterns, the clothing will most likely need lengthened as they're too short.
So, find a different pattern that matches the length you want and look at the back of the envelope. Most of the time, it will have a "finished length". For a knee-length size two, my favored length is 20 inches. If it's longer than you want, somewhere in the middle of the skirt, carefully accordion fold the pattern by however many inches you need. If it's shorter, take your seam gauge and set it for the number of inches you want to add. Pin down your pattern, except for the bottom edge. Then, put it against the bottom line of the pattern and mark with a fabric pencil. Slide the gauge along the bottom line and continue to mark. When you cut it out, simply connect the lines!
I use this technique fairly frequently as I often buy 'child' patterns and adjust the length for my niece, and I've been on a vintage kick since the Vintage challenge. Depending on the length of the original pattern, I may have to add as many as five-six inches or remove the same amount.