When you see Cydia store and how people even manage to sell commercial apps in that "parallel market" there are certainly some guys that could be interested... especially as it would open PC-based develpoment possibilities for the platform, which are pretty much non-existent at this time.
Also, while it might not be very practical to develop on the iPhone itself, it would definitely be excellent on the iPad!
Apple does not allow any third party developer tools for the iOS platform.
The Cydia store has no restrictions, but can only be used on jailbroken devices, which accounts for less than 10% of the total number of iOS devices.