does uclinux1.3 support usb?

No, since the microtronix kernel is 2.6.9, you need to grab the sl811-hcd driver from 2.6.10 -- the internal HCD interface changed in the mainline kernel in 2.6.11, so it would be difficult to incorporate the driver from 2.6.11 into a 2.6.9 kernel without ripping out much of the USB core. (that's what the driver maintainer told me.)

Of course, if you just want to copy over all of drivers/usb, that's probably an option, but I can't speak for how well it works, never having tried it. Frankly, I don't want to have to try it. :-)