The tubular cast on for K1P1 rib looks fabulous, and I love using it. It's described in Catherine Lowe's book The Ravell'd Sleeve (available directly from Lulu).
Some notes:
- Leave the waste yarn in as long as possible, preferably until after the garment is washed and blocked.
- The rib will remain quite tight, you might have to decrease on transition to body, upto 10% or even more.
- I use three needle sizes: a body needle, a rib needle and one size smaller than the rib needle for the tubular bit (aka: tubular needle).
How to
Cast on with waste yarn, using the body needle, half the number of required stitches plus one.
(that will give you an uneven number of stitches; for an even number, skip the very last M1 and purl the last stitch).
Foundation row, rib needle: purl one row with working yarn.
Row 1, tubular needle: K1, M1 by purling through the running yarn.
Row 2, 3 and 4 (row as in "one needle", not the to-and-fro which normally makes a tubular row), knit tubular with the tubular needle.
Row 5 (RS): switch to rib needle and start ribbing.