I set up a server with two network interfaces and wanted to use load balancing and bridging with cheap a cheap non 802.3ad capable switch. Thats why I chose mode 5. See https://help.ubuntu.com/community/UbuntuBonding for further information about bonding modes.
Here is my /etc/network/interfaces file which is working fine till now:
auto lo iface lo inet loopback auto eth0 iface eth0 inet manual bond-master bond0 auto eth1 iface eth1 inet manual bond-master bond0 pre-up sleep 5 auto bond0 iface bond0 inet manual bond-slaves eth0 eth1 bond-mode 5 bond-miimon 100 bond-downdelay 200 bond-updelay 200 hwaddress 00:1d:7d:0c:ca:98 auto br0 iface br0 inet dhcp bridge_ports bond0 bridge_stp off bridge_fd 9 bridge_maxwait 5 bridge_maxage 12 bridge_hello 2