Americans trading securities with other Americans, is this a gray area or fully legal? I do not really know.
That is a red herring, totally irrelevant.
@Goat:
Regardless of the lawful or unlawful nature of floating an IPO on GLBSE in any particular jurisdiction, you already did it. You already got a bunch of peoples' bitcoins for what may or may not be considered a "security" in one or more countries or states. Wasting time doing a bunch of legal research now accomplishes nothing.
Providing Nefario a copy of your passport (or whatever info he's asking for) changes nothing in the eyes of the law.
Your best bet to save face publicly (and cover your ass) is to jump through his hoops to get your account unlocked and pay the dividend(s).
That will probably keep your current investors from wanting to come get you (lawfully or otherwise).
Then you can decide what to do next... continue as-is, or, if you have no faith in Nefario or GLBSE, or are uncomfortable with the questionable legality of the securities you issued, your best bet is to buy back the securities you sold.
Regardless of how mistreated you may feel, ending this drama quickly and to the benefit of your investors will make you look more professional and save your rep.