Hello again,
Apparently the current conveyor is used as part of anther device, such as a current mode op amp. That means it might not be available as a separate device in itself. For example, Maxim makes some fast current mode op amps which have a BW of 1GHz. That should be able to handle 8MHz.
Aside from that, maybe you'd want to build one yourself, but it may be hard to do with all the transistors, depending on accuracy needed.
National Semiconductor, when they were around, used to make a integrated circuit transistor that i think would behave in a similar manner, but i dont remember the part number. It may not be fast enough anyway.
Another way to view the current conveyor in a simpler way is to think of it as an NPN transistor with zero base emitter voltage drop, infinite input impedance, and Beta of only 1. That would mean that any voltage that is applied to the base shows up at the emitter, and any resistor from emitter will draw a current, and that current will be mirrored in the collector given a Beta of exactly 1 and zero input base current. Any collector resistance would drop Ic*Rc and thus there would be a voltage gain.