While reading the other posts I got to thinking of alternating crochet and knit drop stitch (yarn overs that are dropped off the needle the next row, in case I'm using the wrong term) could be an interesting combination, I'm not sure how you'd do it.
Another thought. If you worked the row before you swith to knit in Tunisian crochet you'd already have the stitches on the needle. Tunisian is thicker and stiffer than regular crochet and knitting but it might be OK in this case. I dunno.
You can't knit the left sock first. Ever.