I haven't seen the particular brand you linked to outside Europe, but there are others.
Teleskop-Express is probably the site to check if it's that brand you want.
I bought a SkyWatcher dual saddle (both narrow Vixen-style and wide Losmandy-style) for my NEQ6 (it originally came with the Vixen-style saddle only). I got mine from Astro Pete's for a pretty good price - much cheaper than other options - it's a special order, though, that'll take a while to come in as SkyWatcher (Synta) only ships to Aus about 4 times a year.
Orion used to sell the same thing for their Atlas mount (black version of EQ6) but they don't seem to be available anymore.
ADM accessories make a variety of after-market saddles to suit (including a Losmandy-style "D series" as they call it):
D Series Saddles
ADM saddles are quite popular but overkill, IMHO. Make sure you select the correct "hockey puck" for your mount. ADM also make quite a few other accessories including dual saddles.