If you are handing out (long lived) references to your elements, then yes, you cannot relocate them. In that case, you need an array of pointers, rather than an array of inline values. In this case, your memory use will become even more fragmented, though.
Either way, make sure you have swap space, and you should be all right, especially if the swap is usually just holding idle slop. 2 GB (2^31 bytes) is still a pretty big address space for many purposes. It will hold about 500 4 MB buffers (512, less overhead).
P.S. - I never had to deal with 8-bit machines, but spent plenty of time on 16-bit machines. 32 bits is a big address space, despite Microsoft having pissed all of it (and a CPU core) away just to load the OS, leaving little-to-nothing for actual work.
Either way, make sure you have swap space, and you should be all right, especially if the swap is usually just holding idle slop. 2 GB (2^31 bytes) is still a pretty big address space for many purposes. It will hold about 500 4 MB buffers (512, less overhead).