Another option would be to use SRAM GripShift -you can get shifters (though I realize not everyone likes GripShift) very cheaply on Ebay (got mine for my trekking bars for around $18 including shipping). The grip shifts are usually not just 3 positions but have many indexed clicks, so you can still use them with the road front der.
Of course you'd still need to get brake levers, but if you have a spare pair around you can use those, or again, you could buy some off ebay or an online store pretty cheaply. If you are running canti brakes, you'd need the old style short pull levers (I also got mine for $10 for the pair from an LBS). I think Tektro makes dual long/short pull levers.....