> something like Tabor could have been produced about as early as the X1000.

Yes, but that would have meant postponing the X1000 instead.

> our current systems, with the promise of future X5000 support [...] places limits
> on the utility of both SMP and 32bit addressing, as many of our systems have
> a single cpu and only a few support more than 2GB of ram.

If MorphOS gets SMP support or 4 GiB RAM support, I'm sure a significant percentage of MorphOS users will upgrade to a used machine that can work with both (i.e dual-CPU PowerMac G5) or either (dual-CPU PowerMac G4 for SMP, single-CPU PowerMac G5 for 4 GiB RAM). Besides, even a 2 GiB machine would benefit from 4 GiB RAM support, as the I/O address space wouldn't any longer collide with the RAM addressing, so we'd have full 2 GiB RAM at our disposal instead of the 1.5 GiB we have now (or the 1.7 GiB announced for MorphOS 3.10).

> If we are going to support 4GB and 32 bit, why not 64 bit (and a lot more range)?

64-bit MorphOS wouldn't work on any of the currently supported 32-bit machines (i.e. everything except PowerMac G5 and X5000). And I'd guess m68k compatibility would suffer less from expanding addressing to 32-bit than it would do from expanding to 64-bit.