Thanks for clearing this up. Finally got it to work by using the armv7 packages and specifically the wireless-5.10.77-piCore-v7.tcz package.
I used this to pull the WiFi packages instead of what I had above :
for pkg in ca-certificates libiw libnl ncurses openssl readline wifi wireless-5.10.77-piCore-v7 wireless_tools wpa_supplicant firmware-rpi-wifi; do for f in $pkg.tcz{,.dep,.info,.list,.md5.txt,.tree,.zsync}; do wget http://ftp.nluug.nl/os/Linux/distr/tinycorelinux/13.x/armv7/tcz/$f; done; done
Then, in /mnt/mmcblk0p2/tce/onboot.lst, add the line
wireless-5.10.77-piCore-v7.tcz
just before the line that was there for firmware-rpi-wifi.tcz