I have an older generation Antec Sonata case that I've turned in to an unRaid server some time ago. It has served me well, however, I need to add space for more hard drives and have three 5.25" drive bays I can utilize. I have done some research and it seems like the best product to do this is below:

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16835110018

 

For those that have been there, do you agree? Is there another product I'm possibly missing which might be better?

That device allows three drives to be mounted in two slots.

 

This allows four drives in three slots, but you may have to bend the drive support tabs out of the way in your case to allow it to slot in cleanly.

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817993002

 

There are more expensive options where the drives can easily be unplugged and removed from the front, including 4 and 5 drives in three slots, but I find the Coolermaster unit is good for the price.  It's also available in the UK from Scan at just under £12 plus delivery charge (I just bought three from their eBay outlet).

 

www.ebay.co.uk/itm/Cooler-Master-Full-Alloy-4-in-3-Devices-Module-Ideal-for-Most-cases-/130825964984

 

 

Great suggestion! Thanks for mentioning it. It now has me considering hot swappable options but the the upgrade path is a slippery slope when really this is all I need. Thanks again.

Thanks again for suggesting this product. My cache drive was at 37 degrees with no nearby fan in the 3.5" bay before. In the new cooler master product the same drive is stable at 7 degrees less. I hadn't read good things about the fan that came with the cooler master product so I replaced it with a 3 speed antec fan, but these good new readings are with the fan only on low so it may not have been necessary.

Interesting.  I will be rebuilding my server very soon.  I will start wit the stock fans running with some speed reduction, but I have others that I can use if needed.  Trying to balance cooling vs noise is always a challenge.