So, the 'cheap' one ($20 USD) I mentioned was a Mokertech box from Amazon.
The one I'm using now, that seems brighter, is a TrendNet 4port switch with an SFP port. I chose it based on the recommendation of Small Green Computer's website, which recommended the TrendNet brand switches for their fast packet handling. It's not expensive -- $60 USD.
The big question for me is, whether it's worth trying the Sonore Mini FMC ($110 USD) or to pony up for the $600 USD opticalModule Deluxe.
Have to do some research on FMCs to see what the consensus might be. What's your take/experience?
Best, JAMES.