+1 on midwayusa.com, I'd also check opticsplanet.com as they may have a sale going. I picked up my Safariland 333 speedloader holder on sale. Safariland also makes good leather versions, not sure if Gould and Goodrich make speedloader pouches or if Galco does.
Since you don't want open top, I'll not suggest a polymer or kydex product like the Safariland 333.
You'll want leather, the nylon stuff will work but it won't give you the protection that the leather will. I've found that the nylon tends to move around a lot and often doesn't keep the speedloaders in an upright position (they sag).