I've been planning to make some Leave In Conditioner for months now. (Ever since the last of my Aveda Smooth Infusion Style Prep Smoother ran out and I've been too cheap to buy more.) I finally did and boy am I glad I decided to try it - I love it! I modified a recipe I found here. If you want to make your own bath or beauty products, I would definitely recommend Susan's site Point of Interest. She's got tons of good information and recipes!
Here is my version:
Leave in Conditioner
2% Incroquat BTMS
1% hydrolyzed protein (cromoist)
1% essential oil (10 drops each of rosemary, cedarwood, clary sage and lemon)
1% preservative (optiphen)
water to 100%