I really like those starter models too for a number of reasons.
I converted about 50 of the archer models by cutting off the arrows, keeping the quiver, putting other baggage and equipment on them, doing arm swaps with torches and the random weapons, and made them look like a couple of units of looters. My inspiration was the two metal special models they released way back when - one carrying a pig and a torch, and another with a spear and torch.
The double choppa guys are great too, because 2/4 of them have more armour, which is better than the 1/4 from the plastic multi-pose set, which means they make good 'Big Unz' as they look like they are equipped better.