I found cute little floral buttons in exactly the right colors in the beading department of Micheals. It did require that I rip out and reknit the buttonhole band with larger buttonholes, but it was worth it. Ironically they are now the size they were supposed to be in the first place. I had purposely knit the holes smaller as I usually prefer a smaller button and a YO, K2tog buttonhole.
This is my version of the "Rugby Romper" a free pattern from the Lion Brand website. I knit the smallest (6 month) size and substituted "Patons Astra" for the "Lion Brand Baby Soft". I used nearly 2 - 50 g balls of black as the main color and 1 ball of each of the contrasting colors: Hot Blue, Electric Blue, Hot Green, and Hot Pink.
Alterations: Between each band of bright color I added a 2 row garter stitch stripe of black to make the colors "pop". I used six buttons instead of eight and knit the sleeves from the top down, I cast on the leg cuffs with tubular cast on and I bound off the remaining ribbing edges in tubular bind off.