In that case I also see no difference in owning shares in MPEX which would mean buying even 1 share makes you liable for all its debts public and private and satoshidice since both are "unregistered companies"
The fact they are misleading people into unlimited liability is unfortunate.
As far as I'm aware, holders of unregistered securities - which is what MPEX is set up as - don't generally have unlimited liability in the US. (Setting up an unregistered security is of course illegal in the US and many other countries, but it happens fairly frequently.) It's a good thing too, because otherwise that'd make it a lot easier for scammers to operate.
The reason you're probably in deep shit is because GLBSE/Bitcoin Global has effectively been operating like a partnership. MPOE/MPEX shares are non-voting and their owners have no say in how the company's run, whereas from what I can tell you've been taking an active role in day-to-day operations.