Start screened rsget.pl (add it to autostart/.xsession/):

screen -wipe
. ${XDG_CONFIG_HOME:-~/.config}/user-dirs.dirs
screen -ls | grep -q rsget.pl || XDG_DOWNLOAD_DIR=${XDG_DOWNLOAD_DIR:-$HOME} screen -d -m -U -S rsget.pl rsget.pl ${XDG_CONFIG_HOME:-$HOME/.config}/rsget.pl/list

configure your rsget.pl to use XDG_* dirs and to send dbus notifications:

$ grep -vE '^(#|$)' .rsget.pl/config
backup = done,continue,scratch
backup_suf = ~
max_slots = 8
max_slots_check = 8
workdir = ${XDG_CACHE_HOME}/rsget.pl
outdir = ${XDG_DOWNLOAD_DIR}
use_svn = update
debug = 0
verbose = 0
postdownload = notify-send $(source) "$PWD/"$(file)": "$(name)

configure DOWNLOAD_REQUEST event handler in uzbl config:

set rsget           = sh "echo '%r' > $XDG_CONFIG_HOME/rsget.pl/list"
@on_event DOWNLOAD_REQUEST @rsget

you may also add following binding

@cbind  dd  = request DOWNLOAD_REQUEST "\@uri"

try it! navigate to some youtube.com video, and press dd