yup....casein is the best for slow absorption. I can't give you a name because there are so many out there.....just look at the contents before you buy it.
the yolks have a more complete amino acid profile then the white so by throwing some yolks in you are just upping the bioavailability. You certainly could throw some Peanut butter in with your night time shake to help slow absorbtion. I myself have as of lately been having a vanilla casien shake with 2 tbls of natural peanut butter thrown in (it tastes like a reeses cup mcflurry).
my reason for not doing that is because eggs are a hell of a lot more satisfying and also because they run about $.79 a dozen so that works out good for me too.