Besides cable companies and fast food restaurants, what other items could be sold under product bundling pricing?
The major point of product bundling is to put together items in order to get customers to buy things they ordinarily would not buy. One of the major examples of this (other than the ones you mention in your question) is done by telecommunications companies. For example, many telephone companies offer traditional telephone services (which may themselves be bundled with things like call waiting and caller ID) in bundles with cable TV and high speed internet access. The telecommunications companies hope to to sell to consumers who might otherwise have bought the different services from different companies.
Another example of bundling can be seen in the "trim lines" that car companies often offer. The car companies do not offer all of their options a la carte. Instead, they tend to offer groups of options bundled together in trim lines. Again, the idea is to sell options that might otherwise be unpopular by bundling them with more popular options.