Launched today is the Credit Suisse FI Enhanced Big Cap Growth ETN (FIBG) which is doubled-levered and linked to to the Russell 1000 Growth index (IWF). A similar offering from UBS (FBG) launched in May and it's up 36.8% since.
Both ETNs are "bespoken," meaning they're not for the wider investing public, but instead for a group of high net worth individuals and institutions looking for custom exposure via an ETN.
FBG has an expense ratio of 1.2%, but FIBG - like many ETNs - has a tricky-to-figure "investor fee." Similar - but definitely not exact - exposure may be available through the ProShares Ultra S&P 500 ETF (SSO). SSO is an ETF and rebalanced daily, while ETN rebalancing is only triggered at certain price points.