Will it work?

/ ip address
add address=1.1.1.50/24 network=1.1.1.0 broadcast=1.1.1.255 interface=Local comment="" \
disabled=no
add address=10.111.0.2/24 network=10.111.0.0 broadcast=10.111.0.255 interface=Public2 \
comment="" disabled=no
add address=10.111.0.3/24 network=10.111.0.0 broadcast=10.111.0.255 interface=Public1 \
comment="" disabled=no
/ ip firewall mangle
add chain=prerouting in-interface=Local connection-state=new nth=1,1,0 \
action=mark-connection new-connection-mark=odd passthrough=yes comment="" \
disabled=no
add chain=prerouting in-interface=Local connection-mark=odd action=mark-routing \
new-routing-mark=odd passthrough=no comment="" disabled=no
add chain=prerouting in-interface=Local connection-state=new nth=1,1,1 \
action=mark-connection new-connection-mark=even passthrough=yes comment="" \
disabled=no
add chain=prerouting in-interface=Local connection-mark=even action=mark-routing \
new-routing-mark=even passthrough=no comment="" disabled=no
/ ip firewall nat
add chain=srcnat connection-mark=odd action=src-nat to-addresses=10.111.0.2 \
to-ports=0-65535 comment="" disabled=no
add chain=srcnat connection-mark=even action=src-nat to-addresses=10.111.0.3 \
to-ports=0-65535 comment="" disabled=no
/ ip route
add dst-address=0.0.0.0/0 gateway=10.111.0.1 scope=255 target-scope=10 routing-mark=odd \
comment="" disabled=no
add dst-address=0.0.0.0/0 gateway=10.111.0.1 scope=255 target-scope=10 routing-mark=even \
comment="" disabled=no
add dst-address=0.0.0.0/0 gateway=10.111.0.1 scope=255 target-scope=10 comment="" \
disabled=no

I think that will not work
I have the same problem, how to make load balancing on the same gatheway?!

first is would suggest that you DO NOT USE PUBLIC ADDRESSES

second maybe in this page you could find something useful:
http://wiki.mikrotik.com/wiki/Routing

I think it is not going to work because you have to public IP-s of the same class. as you writte it down in your configuration:

add address=10.111.0.2/24 network=10.111.0.0 broadcast=10.111.0.255 interface=Public2 \
comment="" disabled=no
add address=10.111.0.3/24 network=10.111.0.0 broadcast=10.111.0.255 interface=Public1 \
comment="" disabled=no

the two IP-s, 10.111.0.2 and 10.111.0.3 are of the same class, on the same broadcast, they got to be different, like the second should be sth. like 10.111.1.2