You asked for comments about supporting the non smp version of the kernel.
I have a PI and a PII machine. I have Slackware 14.0 installed on both. I don't use them often, part of me screams to retire the machines, but I still tinker with them occasionally. I do not use the smp kernel with those machines.
I don't remember whether I ever tried using the smp kernel. I'll try to find time to tinker with the smp kernel on those machines. My primary concern is the PI system. I know from experience that many Live CDs no longer function on that machine because most are now built with kernels that only support i686+.
On the other hand, I could build my own kernels. I did that for many years. The past couple of years I stopped doing that, choosing instead to just use the generic kernel and an initrd.
The smp kernel doesn't work on the PI system, resulting in the infamous failure message "This kernel requires the following features not present on the CPU: pae cmov." The smp kernel works on the PII machine.
Pat, if you decide to stop supporting the non smp kernel, that would seem to modify the basic Slackware requirements from i486 to i686 because the smp kernal no longer will run with anything less than i686.