If you are a risk taker and would like to do daytrading with cryptocurrencies, gold, the dollar and the eurodollar, take a look at Gatehub.net. They seem to have gateways for trading Ripple with gold (XAU), the dollar (USD), bitcoin (BTC), ethereum (ETH), ethereum classic (ETC), augur (REP) and the eurodollr (EUR).
They are fine except their volumes suck and it's very tough to make any significant purchase there. It takes ages for that. For a day trader, they have such a small selection of cryptos, that I also don't think it's an ideal platform from that perspective either.