While I don’t know of any 100% perfect projects for this, there are some out there. A quick google shows Pollen — https://github.com/dustinkirkland/pollen which appears to do this, but they it would need to be modified slightly to read from the TrueRNG dongle instead of their pseudo random number generator.
Rolling your own should be fairly easy too in the same manner. Using say apache with SSL enabled, you can make a https connection to your server’s cgi (perl/php/what have you), and POST the length of entropy you want, then fetch the number of bytes from the device or /dev/random (your mixed pool being seeded by TrueRNG), and return that back encoded either binary or hex/json or even printable numbers like random.org. Then use that entropy how you want… or insert it into that machine’s /dev/random pool (this part is a little more tricky). I could see someone rolling this engine out fairly easy.
Since /dev/random and /dev/TrueRNG are both character devices, they should be fairly easy to deal with just like reading a file.
Good luck!