Pentium Dual Core E2140(1.6GHz, 800FSB, L2 1MB, rev.L2)
These have quite advanced thermal protection, so it should work well with passive cooling.
http://www.tomshardware.com/2007/09/27/what_if_your_cpu_cooler_fails/
Quoting from the above "Finally, the Pentium Dual Core E2160, which is a low-cost processor rated at a TDP of 65 W, managed to complete all ten benchmarks with the CPU fan disconnected!"
I'm starting to think of changing a few parts in my VDR as well :) Daniel