I made one more attempt to use SLOTMAN kernel - I tried both ``mark'' and
the plain kernel, since it isn't specified anywhere what's the difference.
The machine won't boot, and remembering vaguely the command trace, I
entered it both times.

That's what I got:
=======================================================
plain kernel:
=======================================================
vm_fault(18e000,f9fff000,1,0) -> 1
type 8 code[mmu,,ssw]:525
trap: type 0x8, code 0x525 v 0xf8ffffff
kernel MMU fault trap
pid = 0, pc = 009F5F04, ps = 2010, sfc = 1, dfc = 1
Registers:
...
...
...
Panic: MMU fault
Stopped at  _Debugger+0x6  unlk   a6
db>trace
_Debugger(8,188c44,f998c,f9623,ff000000) + 6
_panic(f9623,ff000000,0,f,6b8f480) + 40
_trap(8,525,ff000000) + 1e6
faultstkadj(0,0,188e2e,0,1084ea) + 0
_nubus_attach(6b8f980,6b8f480,0,6b8f980,0) + 68
_config_attach(6b8f980,108226,0,0,6b8f980) + 28e
_mainbus_search(6b8f980,108226,0,1081e2,108226) + 2e
_mapply(188e88,108226) + 3c
_config_search(f6664,6b8f980,0,f663a,0) + 56
_mainbus_attach(8,6b8f980,f1181,f1181,f1181) + 1e
_config_attach(0,1081ee,f1181,0,124) + 28e
_config_rootfound(f1181,f1181) + 3a
_configure(f228e,cc,cc000,f227d,1416000) + 1e
_cpu_startup(109060,29d60,8140,80000c92,ffffcffc) + 4b8
_main() + 4a
_main() + 4a
=======================================================
Mark kernel:
=======================================================
kernel illegal instruction trap
trap: type 0x2, code 0x0 v 0x0
kernel illegal instruction trap
pid = 0, pc = 000000028, ps = 2008, sfc = 1, dfc = 1
Registers:
...
...
...
Panic: Illegal instruction
Stopped at  _Debugger+0x6  unlk   a6
db>trace
_Debugger(2,188b60,f9988,f9676,9f6e16) + 6
_panic(f9676,9f6e16,a06e,1,6bf8480) + 40
_trap(2,0,0) + 1e6
fault(?)
_mrg_aline_super(188c3c) + c
_alinetrap(?)
_mrg_SlotManager_Init(0,0,188e2e,0,1084ea) + 2c
_nubus_attach(6bf8980,6bf8480,0,6bf8980,0) + 68
_config_attach(6bf8980,108226,0,0,6bf8980) + 28e
_mainbus_search(6bf8980,108226,0,1081e2,108226) + 2e
_mapply(188e88,108226) + 3c
_config_search(f6664,6bf8980,0,f6636,0) + 56
_mainbus_attach(0,6bf8980,f117d,f117d,f117d) + 1e
_config_attach(0,1081ee,f117d,0,124) + 28e
_config_rootfound(f117d,f117d) + 3a
_configure(f228a,cc,cc000,f2279,1416000) + 1e
_cpu_startup(109060,9960,b2050,80000c92,ffffcffc) + 4b8
_main() + 4a
_main() + 4a

For my future reference: are there certain lines of particular interest to
developers, or is it different each and every time and you would need the
entire thing? It seemed pretty standard to me (or, uniform, rather),
differing in just a couple of places...

But I wouldn't know, anyway. My configuration:

Q650, 24 Meg RAM, 1.3ALPHA (usually I boot GENERIC#47 - BTW, is there an
explanation anywhere as to what's the difference between all these kernels?
I picked mine because I liked the number...), Apple Macintosh II Video Card
1987, Performa+ monitor (I actually tried on both the above and Monochrome
Hi-Res monitor, both separately and with both monitors plugged in). Pretty
much plain vanilla setup. I have the Appoint MousePen, but never had a
problem with it - it behaves absolutely like generic Macintosh mouse
(upside down 8-)). Anybody with similar setup runs MacBSD successfully?
Please respond.

Thank you.

Yuri Oskotsky.