Umm Pork Bellies would be nearly impossible to invest in for an average investor even before they stopped being exchange traded commodities. The margin requirements alone are on the order of real estate investments, not to mention the contract prices.
Well, it's hard to find exact numbers now, but with a daily price limit of 0.03 on a contract of 40000, that's $1200. Figure double for initial margin.
I mean, even if you were to take delivery (!!!), pork bellies traded for less than $1 per pound, so you could buy it outright for less than many real estate deals.