same issue here. a lot of the buddhists in our local communities (we have a lot of different flavors of buddhist here) are families, but the sessions are not family friendly at all.
so, i'm actually starting my own thing.
we own a holistic health center, so i have the space. we'll have an hour and a half "thing" where for the first 5-10 minutes, the children are with us for the beginning of meditation, and then they go to a separate room where they are taught buddhist stories (or fables of various kinds, etc), have toys for open ended play and perhaps some simple crafting supplies. parents will rotate as to who is in the room with the kids (perhaps two parents at a time) week to week.
after a 45 minute meditation, i thought we would have a discussion on a buddhist topic, so that we can just have some time to study together. following that, we would have a brief refreshment time, where the kids would join us.
it would also allow us to create seasonal festivals, too.