I came across a cute little vintage pattern from a 1970s craft book I collected from a thrift store. I tweaked the pattern slightly and came up with these, it would fit a 12-18 month old. I tried to model it on my 11 month old son, but he wouldn't have it! lol...they are both reversible.
I thought that maybe I would like to make one of these in a "big" girl size for me, kinda like an apron, and I found this awesome crafty mama's pinafore tutorial here, so I may have to give this a go too!!