those things sound great. id be interested to see any links you may turn up...
another sort of building blocks going down a treat her at casa nappy are jumbo soft blocks... made of a dense sort of foam. they are quite good b/c the little darlings can chuck them at each other/the walls/the furniture/down the stairs without doing damage to themselves, your house or your ears. always a bonus i find. found mine on ebay. will try to find a link for you...