I actually think it would be quite problematic. First of all, there is a reason why that waitstate is added. The cable and cirquits on one set of extender/receiver cards does add quite a lot of delay, which may be problematic for slower memory or I/O devices if no waitstate was added.
The first problem with several cards in series would be that each set of receiver/extender cards of the chain would add delay, but the number of waitstates would never exceed one as all the sets puts it at the same place. The second problem will be that the pair of cards is not just passthrough buffer, but contains a programmable interface. Adding several cards to a system would ressult in I/O conflicts. These I/O ports are used for example when the interface is initialized by the POST.