I spent lvls 28-32(Troll Warrior)in Echo working the Mutant/rejects caves and the first Boglings right after the big double doors. This guy and Roy gave me the most trouble, you MUST interupt this guy or he will nuke you oblivion. He dropped the Tinker's Tools for me on the fourth kill, other drops were deluxe toolboxes 0% WR 10 slot giant box, not really bad. As with most of the rejects he pops at one of the pre determined spots instead of a mutant. However, if the area has been cleared you might get several of the "named" type in the same room, makes it tough. Overall xp is similar per kill to Paludal, critters just hit harder :) good luck
Bawgg Toadstomper, Troll Warrior of Doom