This probably isn't what you're looking for...but I stumbled across it and thought it was interesting! I would like to try and make it someday...though I'm a little overloaded with slings myself (a New Native, a Maya, and a Rebozo! )
FREE BABY CARRIER:
Turn your old jeans into a sturdy denim baby carrier! You'll need two pair of adult jeans, with no worn spots on the backside. Remove the backs from the fronts, leaving the thick side seams attached to the discarded fronts. Cut off waist-band, belt loops and leg hems. Make a T-shaped cut up the centre from each crotch, as follows: On one jean-back - "T" is through the centre of the back pockets.
On the other jean-back - "T" is midway between the crotch and bottom of back pockets. Fold the legs in on themselves to form 4" wide straps. Double-stitch along the length of both sides of these straps. Place one jean-back on top of the other, to form an "H" shape - lining up one jean-back along the top of the other's pockets. Double-stitch the two jean-backs together.
Tie the shorter straps around your waist. For a front carrier, have a friend help place baby's stomach against your stomach, baby's legs on either side of the carrier seat. For a back carrier, baby's stomach is against your back. Bring carrier and longer straps up over baby, with one strap over each of your shoulders.
For a front carrier, you could cross the straps at your back. While you hold securely on to the longer straps to support baby, have your friend mark or pin where these longer straps meet the seat part, making sure this is a comfortable position for baby and you.
Remove baby and carrier, double-stitch longer straps to marked spots, on the inside of the seat part. Finish by folding and hemming any remaining cut edges. Make sure all stitching seams are strong and sturdy for safety.
.... oops, did I just violate copyright laws? )