http://www.entropykey.co.uk/

I've got one of these on my home server - each one punts out 4KB of good quality entropy per second, and can be shipped across the network to other systems. Just stopped generating a DNSSEC key on my Linode (it had been running since around 8am this morning), generated one on my home server:

casull:~# time dnssec-keygen -a RSASHA512 -b4096 -3 -e example.com
Generating key pair.............................................................++ .........................++
Kexample.com.+010+44938

real   0m2.248s
user   0m1.408s
sys    0m0.040s

Just a thought

I've always been of the opinion, perhaps incorrectly, that blocking on /dev/random instead of just using /dev/urandom is extreme paranoia. Besides, your example requires what, 64 bytes of entropy? Unless you're generating a ton of keys, 4096 bytes per second is crazy excessive. Besides, there are cheaper solutions that are just as random. For example, hoopycat might point a $5 webcam at his dehumidifier and hash the raw data, providing tons of high-quality entropy, both through variations in the image itself, and CCD noise from the cheap webcam's crappy CCD.

His humidifier might be shy, though.