Try checking Patternfish. They have a lot of obscure patterns.

Hi: Measure the elastic around your waist and subtract 2" from the length. Sew the ends together to form a circle. Divide the elastic into quarters and mark with a straight pin. Pin each section to the front, back and two side seams, so the elastic is in equal portions around the waist. Then stretch the elastic as you sew each section, starting at the top. Use a small zig-zag stitch and do at least two rows (one on each edge). Then turn it under and sew again. Hope this helps

OK, I've read your post a couple times Suzi, and I'm not sure I understand about the "turning the gore under and sewing up the middle" part of your hem explanation. However, I may be able to help a little with the rest, so here goes. 1. Decide how many gores you want. Usually there is an even number of them, and usually it is 6 or 8. For a child, I'd pick 6 since kids are small around the middle, and you'd have itty bitty strips if you did 8. 2. Measure the kid's waist and hips. Using the larger of the two measurements, divide by the number of gores you want. Say the child has an 18" waist. Divide 18" by 6 gores. Each gore's finished size is 3" at the top. You'll need to add a seam allowance to your pattern piece. Since you're going to put elastic at the top, all your pattern pieces can be exactly the same. (I'm working on a gored skirt right now that buttons down the front, so 2 of my gores are a different size so that there's overlap for the buttons.) I'd draw the pattern without any seam, hem or casing allowances first. Then add them on at the end. It's easier to think about the pattern piece without all that stuff to begin with. 3. Measure how long you want the finished skirt to be. Probably the waist to knee length you mentioned, but you could also go a little below the knee if the kid is growing quickly. This will be your finished gore length on your pattern. For drawing the pattern, I'd get a cheap yardstick if none of my other rulers were long enough. 4. Figure out how big around you want the skirt to be at the bottom. You can do this by laying out your measuring tape on the floor in a circle. Vary the size of your circle and decide what you want. Take this measurement and divide by the number of gores. Say you liked the 36" circle. Divide by 6 and each gore is 6" wide at the bottom. Here is where you can flare out the gore like a flower petal to make it flouncy or make it REALLY wide and get a circle skirt or whatever you like. 5. Since the hems will be on a slight curve, I would want them to be as small as possible, but you'll have to decide the hem allowance based on what kind of fabric you use. I would do a little rolled hem, but then I'm thinking of a blouse-weight rayon or light cotton. If your fabric is heavier, you'll need more allowance for your hem to turn properly and lay flat. This skirt would be adorable in a lighter denim (with ricrac along the bottom!!) or in a light cotton, so test out the hem size on a scrap. Once you've done a couple you'll have a feel for it. Of course, since your kid probably isn't too picky, it won't matter that much anyway. ;-) 6. Elastic at the top - I'd probably do a 3/4" or 1" ban-roll elastic at the waist BUT I don't sew for kids and don't know what the standards are for them. You'd probably know better what size elastic is good. If your kid isn't handy, just check the kids' clothes section at any store. The casing width should be the width of your elastic plus a small seam allowance (the part turned under) plus enough wiggle room to pull the elastic through the casing (and so the fabric lays properly). The "wiggle room" depends on the fabric. Thin fabric won't need much, but thicker fabric will need more. If you have some scraps, test it out. see how the elastic pulls through about 4-6 inches of your tester casing. I sure hope this helps. Sorry I can't figure out what you mean on that hem thing. :-)

Only other thing I can think of is to make decorative triangles out of a coordinating knit and sew them into the side seams...wide end in the waist band and tapering to nothing in the hip....esp since they are exercise gear, you could add that decoration. Or make it out of a matching fabric and wear longer tops so the seams aren't noticeable.