As one of the lucky authors of Hero's Handbook: Eladrin, I hope you'll find it worth the wait.
A couple of teasers from me: There's a number of feats that let you do nifty things with your fey step. Also a paragon path meant especially for athletic fighters who want to be very mobile on the battlefield, which might suit your charge happy character. As far as background and character-building stuff, there's a good bit of detail about the four seasonal courts of the eladrin--Spring, Summer, Autumn, and Winter. Eladrin of each court tend toward different personalities and roles in their society, and each court holds a feast on the solstice or equinox of their appropriate season. There are also courtless eladrin who were born, not in any proper season, but under the ill-omened Moon of Void . . .
Cool! An answer from one of the authors! I like things that trigger on fey stepping, so now I'm even more curious about the book! As my eladrin is very much into the autumn I was also wondering whether any of the seasonal stuff comes back in the crunch of the book? Because that was what I really liked about the Dragonborn book: those clan feats that combined flavour with crunch...