Question: We have just received a device with 10Gig BaseT ports (for copper cable with RJ45 endings) that needs to be connected to a Cisco Nexus 5548. This switch only has SFP+ ports and we're connecting them right now using a couple 1Gbps SFP. We really would like to use the 10Gig connection.

I googled 10Gig Media converters and found some brands but i have doubts regarding stability and compatibility. The final scenerio would be like this:

[Nexus 5k]--[10G SFP+]---Optical Fiber Jumper---[Media converter]--Cat 6a--[DataDomain]

Does anyone out there have a similar combination of equipment? How has it worked for you?

Answer: 
Third party SFPs can be hit or miss. Make sure to check the compatibility matrix that cisco has. 

If the module is an unsupported module then it will not work right off the bat. There is a command to enable them, but a warning will pop up stating that Cisco doesn't recommend it and that they can't guarantee performance. Also, if you choose to enable the Third Party modules via that command Cisco reserves the right to stop troubleshooting, if memory serves.
The third party components will work fine. If you find otherwise, I would love to hear back...

Don't resell them as Cisco though. People have gone to prison for doing so...

Also, if you tell Cisco TAC they will void your SMARTnet contract out.