Well firewire can support up to 64 and usb can support 128
one
one
48
7
7
You can have up to seven Bluetooth controller devices on a PS3
63
15
3
USB hubs are commonly used to connect several different devices to a computer system. In other words if someone wants to attached several printers, an external hard drive, a microphone, or any number of other devices to their computer at the same time they should buy a USB hub.
On a standard Atx Motherboard IDE specifies that no more than 2 devices per bus, so if you have a 2 IDE bus computer you can have 4 devices. Some computers have 4 IDE busses in which case you could have 8 devices (these use a 'Promise IDE raid chipset') This is just recommended specifications at least, you can always hack and try for more off record lol
An infinite number. It would be AWFULLY slow.