I've found the following vintage knitting patterns that would be fun.
Summerland Sweater on Ravely
1920s dresses seem to be harder to find. There are a lot of reproduction patterns for other decades but it looks like most patterns come in the typical flapper costume or actual vintage patterns. Miss Crayola Creepy has a blog post about finding 1920s patterns online. I think I am going to choose one of the following patterns for purchase from Mrs. Depew Vintage on etsy. She has some cute patterns from other decades as well.
I'll keep you posted on which pattern (or patterns) I choose. Have you found any cute 1920s patterns?