I noticed the other day in a Design Within Reach catalog that Herman Miller is once again producing licensed Eames armshell rockers (and other plastic armshell pieces). I can only guess that the Eamesian (is that a word? It should be.) fiberglass armshell rockers being produced by Modernica were so popular that Herman Miller decided to get back into the business. DWR has them for only $379, which is pretty competitive with Modernica, though they only have four colors to choose from (Modernica has every color you can imagine) and they're made of some sort of new, enviro-friendly plastic. Personally I think the fiberglass looks way cooler.
The modern day dad suggestion? Get a vintage one if you can find it, or if you're too lazy to hunt one down, get one from Modernica like I did. Honestly, it's a chair no modern nursery should be without.