This is impractical in the US as things currently stand; most utilities have a permitting process for a grid tie (anything that backfeeds the grid) and smartmeters are capable of detecting and reporting any backfeed.
Mostly the technical aspects are not a problem (most modern meters are two-way); you'd just need a policy like the one in Germany allowing de minimis backfeed.
If you are actually tying the solar-panel into your house's "grid" couldn't you also make additional mods between your electrical-panel and the meter to prevent backfeed?
Or, maybe an inline battery that the solar panel tops off.
It's a solved problem because this is a feature of most hybrid inverters. The only reason it's not as easy as pie is because of lack of information, and "Scare" tactics promoted by electricity-generation companies.
That said, people are generally using whatever meter came with their house, and few older meters were two-way. If you have an older meter and you start backfeeding the grid, you will end up paying for that electricity as if you had bought it off of the grid. The meter isn't smart enough to know which way the current is flowing, it only knows how much current is going past and assumes that all current flows into the house, not out.
Mostly the technical aspects are not a problem (most modern meters are two-way); you'd just need a policy like the one in Germany allowing de minimis backfeed.