I don't know of one. And to be cynical, I don't think the investment industry really wants investors to understand risk
; it seems to me that it's all about pushing risky investments and playing verbal
games, like saying you can "reduce" risks by choosing the right blends of stocks, and meaning, yeah, "less" risk like dropping 44% instead of 48% in 2008-2009.
What I suggest as a reasonable substitute is to look up growth charts at Morningstar or elsewhere--directions
--for real mutual funds that have real combinations of stocks and bonds. The effect of adding international--either old-school EAFE index or newer total world including emerging markets--turns out to have been very small in the past, and while "how much international" is a contentious issue in the forum, the contention is mostly about the future.
The Vanguard LifeStrategy funds have been around for a reasonable time and while their composition has evolved, their percentage of stocks has been reasonably stable. So, you could, for example, plot the LifeStrategy funds--use the link to the live chart and spend some quality time sliding the mouse over the chart, reading out dollars, and imagining how you would feel seeing your account balance do that--and then look up the composition of the fund that's to your taste. Live chart
--be sure to click "Maximum" if the chart isn't showing all the way back to 1994.
Notice the general pattern here. Risk was
rewarded. But not as much as you might have thought at times.
Most of the time, the four funds are in just the order you'd expect, most aggressive on top, least aggressive on the bottom. (Unfortunately, endpoints, endpoints, it's always endpoints--the picture look different if you start at a different place). And while I really do believe stocks do well in the long run, there is a serious danger of false optimism when stocks have had a good run; you mustn't fooled into thinking, say around the year 2000, that your retirement is in such good shape that you can ease off on your savings; and you mustn't hold so much in stocks that you'll do something foolish when the market plunges.
Another good set to chart is Fidelity's family of "Asset Manager" funds, which are (currently) named according to the percentage of stocks they include. The actual composition fluctuates around the percentage, because they are trying to, uh, time the market, but it doesn't matter much.
Warning: due to the "lost decade" for stocks, and due to the (people exaggerate this but it's true) "thirty year bull market in bonds," beware of recency--in the recent past you might as well have had a conservative allocation because an aggressive allocation didn't help that much, but that is historically unusual.
Annual income twenty pounds, annual expenditure nineteen nineteen and six, result happiness; Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery.