Mikrotik makes a whole bunch of 10G hardware. The 8 port ones are fanless and have a heatsink on the back, and the 16 port model has a fan that only gets switched on when needed. I have one sitting behind me and it's been off all day.
It's also easy to open and replace the fan with something less noisy. Just remove a few screws, it's a standard size with a normal connector on it.
There's also big external heatsink so you could rig up a big, slow, fan to help it out a bit.
If you want to be green by the way, use fiber/DAC. The 10G copper SFP+ modules are power hungry, and Mikrotik recommends not placing them next to each other. Also the extra power draw is likely to result in fan use if you have a lot of them.