I've been using these round 3W 3.3V PSUs from Recom for a few projects a while ago. A bit expensive but very easy to connect and mount, especially within a flush socket housing.

There's also a less expensive 2W mini-brick shaped version.

2 or 3 Watts are way enough for the Omega (it consumes about 1W), but of course you need to take your peripherals (sensors, relays, etc,) into account.