Rooting isn't Android version specific, it is device specific (getting root access to the device). So technically, no Honeycomb can't be rooted. On top of that Google never released Honeycomb source code on its own so for the most part it has not been available on rooted devices and that isn't likely to change now that Google has released the next Android version called Ice Cream Sandwich.
I know that the ASUS Transformer (Honeycomb 3.2.1 currently) can be rooted easily due to an application backup tool that ASUS included. Also, I know some folks with an A500 that is rooted as well.
It can be rooted if someone found a key to the door to get in.