My mother just made us some size 2 'onesies' for DD#2. They have zips (child undoes the snaps and escapes at night) and are better than the commercial ones mainly because of the quality of the zip she uses (you CAN get size 2 onesies - from Best N Less for about $10). We have an escaping nudist who can actually rip apart the chunky plastic zips on the cheap Chinese imports. We have a rather large nappy safety pin holding the top of the zip closed. Best having her warm and covered with a nappy on than naked in a wet puddle on a cold night.

I can ask her what pattern she used if you like?