For a larger chunk of copper, you can also find the Dynatron P12G on Ebay. I have this running in a Morex T3500, and with a 5V 120x20mm Yate, it keeps the CPU at 35-37C idle, <67C running Intel Burn Test (MB = Zotac 9300 ITX, CPU = E5200).
Total height is 26.5mm, and even with a 25mm fan, you are still well under 2.5".