Just to clarify things, for bridge to work, you need two configs (tap & bridge)
config for tap should look like this:
file: /etc/conf.d/net.tap0
config for br0 should look like this:
file: /etc/conf.d/net.br0
If these two configs work, then add stuff like domains, nameservers, routes, mtu's etc...
also make sure, that you actually have IP forwarding enabled on your system (echo 1 > /proc/sys/net/ipv4/ip_forward)
Actual network templates are located in /etc/netif.d/
If you don't like them, you can create custom ones!