First it helps to show what VASGX contains:
Vanguard LifeStrategy Growth Fund:
Vanguard Total Stock Market Index Fund Investor Shares, 48.1%
Vanguard Total International Stock Index Fund Investor Shares, 32.2%
Vanguard Total Bond Market II Index Fund Investor Shares, 14.0%
Vanguard Total International Bond Index Fund Investor Shares, 5.7%
So roughly speaking, 50% US stock / 30% international and 20% bonds.
In general I don't see all-in-one ETFs. Those retirement related funds have an audience that buys and holds for a very long time. ETFs generally are for people with high turnover. What do you need that you think only an ETF can provide?