One of our customers at work makes such equipment - for commercial environments. IIRC I had a discussion with one of their guys a few years ago to find out what they were using - with a view to putting it in our server room. The consideration for it was quite short once I found out the cost of the equipment - which would have been 4 figures even for our small DB
However, the OP may wish to consider something like this.
http://www.delorie.com/electronics/powermeter/
Unlike most "add on" energy monitors, this does calculate true power - there's space on the board for 16 power measurement chips which do all the measurements (voltage, current phase angle/power factor, and totalise it all up) together with a microprocessor that interfaces between these and whatever you want to use to interrogate it.
While I was looking into this some time ago, I came across a few options.
http://openenergymonitor.org/emon/
Don't know if most of the hardware can do true power measurement, or if it's just limited to measuring current and guessing about voltage/power factor. But I did spot mention of counting pulses from your lecky meter.
http://www.billporter.info/2010/12/19/not-so-tiny-power-meter/
Does true power measurement - in software. Only one channel.
http://smartenergygroups.com/samotage/posts/72-The-SEGmeter-specification
Another DIY system - dunno if it does real energy monitoring.
http://www.brultech.com/products/ECM1240/default.htm
Something commercial.
A common things whatever you choose is that to get true power measurement (rather than a guess) requires the system to measure all three of voltage, current, and power factor. The chip used in the first project at delorie.com does (from memory) many measurements per cycle and does instantaneous power calculations - which it then integrates to get a value useful to us. Some simply look for something like zero crossings to work out phase relationship - which is better than nothing but isn't necessarily accurate with non-linear loads. The cheaper options don't bother - so all of those "energy meters" that just clip round one of your meter tails are absolutely
NOT energy monitors as the only thing they can measure is current - no voltage, no power factor, and so only a guess as the actual power.
Also common to all projects that measure each circuit in your CU - you'll need to be going into the CU to attach the CTs (current transformers). It shouldn't need saying that inside a CU is a hazardous place and you shouldn't go in there if you don't know how to work safely. Unless you use "clip on" CTs, you'll also need to be disconnecting cables - and it's easy (more easy on some boards than on others) to miss the clamp when putting them back.