e_shadoe,
it does not matter if you're canadian, australian, japanese or italian. once you create a US corporation entity, the entity is doing the trading not you. Any broker will open you an account in US.
it does take some paperwork to avoid double taxation though. it's all legit too. anyone is allowed to invest in a corp. I don't know if a LLC is more scrutinized than a C-Corp. maybe. a C-Corp is bullet proof, but you pay more taxes up front than LLC (because the corp is taxed, and the money you remove is taxed too, through dividend and / or manager fees, salary etc...).
LLC is usually the best for a US resident. but I am not sure it is the best for a foreigner. maybe.
tntneo