Dedicated Micros. Their DV-IP should do the trick. If not, the D4 will definately do the job and then some. These are some really well engineered dvrs.
[Link: dedicatedmicrosus.com]For the life of me I cannot recall the brand/model of the rackmount DC power supply we used but it put out more +12 then I knew what to do with. Four Euro barriers for 24 individual outputs. Considering the number of cameras, audio pickups and IR illuminators, it was well worth the cost.