There is a couple of motherboard which could be added to Libreboot, notably :
Intel G41/ICH7 :
ASRock G41C-GS R2.0 (Still sold brand new, DIP8 socket)
Intel Atom D410 :
Intel D410PT (similar to D510mo)
Thanks for bringing these to our attention! We'll look into these and, if feasible, support will be included in our next release.