Impressive.. And hopefully it scales to support that
Two points,
1. So is a single issuer limited to 3 letter "Currencies"? So a max of ~17,000 combo's? Or is that just a restriction of the current client?
That's a client restriction. Internally, a currency is a 160-bit integer. One part of that namespace is mapped to three-letter currencies which also have a 16-bit 'version' (in case a currency is re-issued). Another part of that namespace is intended to be hashes of a "currency description". I believe custom currencies were discussed elsewhere and the basic idea is that development hasn't progressed much on them because of a lack of good use cases. The core of the system basically just treats them as 160-bit opaque values.
2. Taking commission on trades is probably the most profitable part of running an exchange, using ripple the trades would be free? Existing exchanges might be hesitant to support ripple given they will be sacrificing their own profits to support free trades?
It is the nature of new technologies that business models have to change. Just ask the recording industry or the buggy whip manufacturers.
Suffice it to say that the exchanges we've been talking to haven't had trouble finding new business models that work with Ripple and, if Ripple succeeds, the old models might run into some trouble competing. If you don't think Ripple will take off, it's no threat. If you do think Ripple will take off, talk to us. There's lots of room and opportunity.