Also since forward is settled between two parties it can be done via multisig escrow, so there is no need to trust exchange your money, at least in theory.
(I'm sorry if it looks like an advert for my non-existent service, but I was discussing this topic with Fireball before he made ICBIT and I wonder what people think about it now. That's all.)
What you indicate here would be a more advanced kind of platform, technology-wise. Exactly that kind of development the bitcoin trading community would badly need, to get out of that situation where you're forced to expose your BTC when you need to hedge or want to trade. So, from a theoretical point of view (or let's call it bitcoin project roadmap), such a platform would be very desirable.
Regarding the actual market demands. Yes, there is need for leveraged trading (both because of speculation and because of the need to hedge with limited risk exposure). My gut feeling is that there is enough demand to support several offerings.
On the other hand, it looks like even very basic financial instruments are still a bit of a challenge for many community members. A good example is the complete failure of the BitcoinOPX platform this summer. Probably this was partially due also to usability problems, but such could have been worked out if people really wanted bitcoin options. Indeed, it is a bit surprising, that there isn't more demand for options. Maybe everyone loves Contracts-for-Difference, since these are easy to grasp. You know, "If war is God's way to teach geography to Americans, then Bitcoin is God's way to teach geeks economics!"
However the downside is that initial margin might be considerably higher than you have with ICBIT futures. (But it's up to market players, it might be tiny if they are OK with small profit caps.)
Would that mean that, when placing a bid/ask, you would also indicate the provided margin, so the counter party could make an educated decision if (s)he wants to enter into such a contract?
