I had a customer ask me to make a longie for her baby that was striped with 7 different colors. Usually I stop at four colors as knitting more than that on the machine is problematic. I have a four color tension guide from my standard gauge machine set up on my mid-gauge & it works well. Using more colors means having to hand feed some of them, & I don't like to do that. When I do multiple colors I run the yarn up the right side of the knit if not using a color changer. The mid-gauge doesn't have a color changer so you are changing colors by hand. This particular pair of longies had 7 colors with 4 repeats.
I had so many ends that carrying up the side was not working. Too bulky. After the cover was off the machine I Kitchener stitched the yarn ends on the wrong side. I didn't really like that method but that is what I used. After I finished I did a search on You Tube looking for ways to knit in ends while making the garment. I only found a couple videos including one from the Answer Lady. I haven't tried it but am going to knit up some swatches & see how it works for me. I hope she doesn't mind my uploading her video to my blog. I emailed her but she didn't respond. Let me know what other methods are out there & if you have ever tried this.
I remember that I made several jackets one time & did an e-wrap on the side where I put the zipper to give it more stability.