Wristnetworks, take a look at
http://lkubb.dns2go.com (but you have to register your nick to use it). When you create a new topic/reply/edit your post, there is a URL to the upload form (btw, in mine it's ultimatebb.cgi?ubb=upload_form but in this one it's upload_form.cgi but it doesn't really matter).
You can also choose in the CP to use a random number, member number or member name to the file. I chose Member #.