Yes, the CPU is soldered on on all Tanzania clones. However, there are G3 upgrades available that plug into the L2 cache slot, that are designed just for the Tanzania based Macs.
not right... there were tanzania clones taht used a ZIF socket for the CPU
and there were g3 upgrades for this socket too...
EDIT: these machines were the ones with a tanzania with ZIF connector: Umax Apus 2000/3000 and SuperMac C500/600
the g3 upgrade for these machines:
http://www.xlr8yourmac.com/guest_rev1/powerjoltgmax/index2.html