MEANWELL makes enclosed DC/DC PSU's with regulated 5V@10A (50W) output and 9-18VDC input for $36.
There is also a 5V@5A (25W) version which is half the size but more expensive, $41.
Jameco has them
50W output
http://www.jameco.com/webapp/wcs/sto...48&pa=212548PS
25W output
http://www.jameco.com/webapp/wcs/sto...61&pa=175661PS
They also have 12V output PSU's.
Only downside is that the PSU is a bit on the bigger side but when you have 20 usb devices... its well worth it. I'm gonna use to power all my USB stuff. Nowdays even my phone chargers are usb as well so it will serve multiple purposes.
Found 5V@10A PSU to power USB hubs, devices, etc
Linear Mode
