1.  Why in the *world* is this kernel so damn big?  2.7M vs 1.6M...

it needs to have a filesystem in it.
   
   2.  How do I get a root filesystem in there?

see src/distrib/sparc
   
   3.  What else needs to be done?  I assume this is a SSTO floppy,
   	more or less, vs. the DSTO set we used to use (am I wrong?).

see #2.
   
   4.  This should probably be question #2:  Is there a document on this
   	anywhere?  (I must be blind -- I can't seem to find one).

building sparc releases?  not really.