So any cash-based business is good. Restaurants, car washes, pawn shops, bars/clubs, etc. These types of businesses can make thousands per day gross and are relatively easy to run with low capital down. That's going to be far superior than shipping hundreds of overpriced hard drives per week via e-commerce and hoping to god no one traces back all these credit cards back to you or your pals.
You can learn the basics of accounting and laundering over a weekend if you had to and learn just enough to avoid being flagged by the IRS. Hell, some accountants specialize in these kinds of things.
I also think that you need to accept some level of risk here and that you'll be dealing with audits periodically. Auditing isn't some scary process, more than likely you'll be dinged for more taxes and not be put in jail. You'll come out ahead, especially when you consider outsourcing laundering is very expensive, something like 50-70% and depending on how it comes back to you, that money is also taxable, so another 25% lost on what's left. Running your own business means you only lose that 25% and some overhead.
There is an enormous financial black hole that is just as vulnerable to inspection as simply depositing $1,000,000 in cash in your account. The whole point of money laundering is not only to legitimize the output, it's to make the sources untraceable and arguably viable as well.
The components of a transaction, particularly for the sales of goods, cannot simply appear out of nowhere, or they've done absolutely nothing in the way of money laundering. The people who will ever care about this (the ones who money laundering is constructed to fool) aren't so naive, and if you're selling 100,000 hard drives to justify your income, they're going to ask where you got the hard drives, and demand a financial trail.
Cash businesses that have little variable costs outside of manpower (such as carwashes, laundrymats, even some small restaurants, or selling small crafts on Etsy) are absolutely lucrative tools for money laundering, and can only really get caught if put under heavy scrutiny (e.g. car wash with 10 cars over the week claims revenue of $100,000). As are casinos, and Vegas was built on money laundering -- there are few checks on how much you spend, so whether you spent $1,000,000 in unexplained cash to leave with $950,000 in legitimate winnings, or $10 in legitimate cash to leave with $950,000 in legitimate winnings, it's almost impossible to prove.
There are many, many financial vehicles that are used for money laundering, including life insurance. Selling hard drives on Amazon is not one of them.