On the memory use for the 32K space, since you are splitting it into 4K zones already, you might want to take a look at using the switching scheme used by the SAMS card (you would have to extend the latching scheme of the 74LS612 it uses by two bits to use the entire 64MB space though, as it currently maxes out at 16MB). That will keep you compatible with software designed to see that extra space and it will allow you to take advantage of the memory in a seamless fashion.
Thanks Ksarul - in fact that is what I have been trying to do. At this point it is very simple, in addresses >5000 to >501F there are sixteen paging registers, 16-bits each, out of which bottom 14 bits are used. To my understanding this is how SAMS works too. I don't have CRU support yet, but I will be adding it shortly, in order to implement the same enable bits as the SAMS card uses (currently mapping is enabled via memory mapped control registers, but that will disappear when I have CRU support done). I have been using Thierry's page at http://www.unige.ch/...99/superams.htm as the source of information, is there something else I should be looking at too?