Bro, until today, its been years since i tried to call an order in. but to answer some of your post, unless asked, Ameritrade does not tell you anything in regards to why you have to call it in. and i doubt it has anything to do with liquidity issues; its more likely in regards to the perceived liabilities that come with having to use their own clearing house. fwiw, ETrade clears a lot more pink/pennies.
in the case of MCHN, AT does not deal with stocks that require physical holdings such as certificates for trading.
btw... would have got back earlier but i was away sans notebook and i don't do text on the Droid. sorry fer' the delay.
best to ya'
rich