SPI not working on ATtiny441
Eureka!  Turns out the SPIMAP bit is incorrectly mapped!

/usr/local/CrossPack-AVR-20131216/avr/include/avr/iotn441.h:377:0: note: this is the
location of the previous definition
 #define SPIMAP 0
 ^


(It should be bit 1.) Therefore, the line remapping the SPI pins was failing!  This is corrected by placing a #define SPIMAP 1 in the #define section.

EDIT: As Martin pointed out, I am indeed using an old version of avr-libc.  I was using the latest version of CrossPack, which is dated back almost 4 years from today.  The newest version has this bug fixed.