Baby leggings were what I had in mind. I'd read a few tutes for them and they seemed like they should be ok.
I tried to get a twin needle for my machine but the local craft shop where I know they stock them was closed today, and the other fabric shop had an assistant who did not know what a twin needle was. (She offered me knitting needles first, then size 16 machine needles, then, unsurprisingly, I left.)
So I just jumped in with what I had on my machine. Turns out my machine has a lot of fancy stitches well capable of dealing with stretch fabric. (Not that I knew what any of them were.)
I used a pair of leggings Rachel already owned to make the pattern following this tutorial. Then I tried out some of the overcast stitches on my machine. I still don't really know the difference between some of them, they seem pretty similar, but I used one for stretch knit fabric and it seemed to work ok. (It was number 21 on the picture below)
The machine told me to use this fancyblind hem foot when I picked the stitch (no idea why though). I like how it looks and it seems nicely finished though.
These were really straightforward to make. I liked the finish I got using this stitch on the main leg and front and back seams. However, I didn't really finish the raw edges on the hem turn-under as nicely as I would like - I was trying to overlock them before sewing the hems on the bottom of the legs and it stretched the fabric a little. I know they won't fray and it won't be noticed, so it's not a big deal but I'd like to figure out how to finish them a bit more professionally. I also was a little messy sewing up the casing for the elastic at the top. But overall, they're details only I would notice.
Miss Rachel tried them on and seemed very comfortable in them. I think I'd go a couple of inches longer next time but they fit pretty well now. I had fun making these and I'll definitely be trying some more dress making in future, I haven't done it for a long time and forgot how nice it is to make something for someone to wear.