>   1) Is the above CPU supported/been tried?

Has been tried.

>   2) Can I use "any old SCSI disk" ?

Older ones are more likely to work than newer ones...

>   3) Can the kernel go multiuser?

Yes.

>   4) If [3] is yes, how stable is everything? is anyone running any
>      real apps like a news feed or supporting several users doing anything?

I used to run my internet connection through a 5k/25 running NetBSD,
and was quite happy with its behaviour in general.   The only thing
that stopped me was that the hardware failed.   :'(

			       _MelloN_