Anyone recommend a good chip supplier?
It's coming up to fruit tree pruning season, so spread the word and make sure you collect up some of the offcuts for drying. Won't help you now, but it will help a few months down the track.
Other than that, I've used chips from BBQ Galore (they were alright, not great) and Bunnings (hickory chips were really nice). Or you can dry your spent grain, mix it 60:40 with uncooked rice and smoke with that? I've tasted the results from someone who does that and it's pretty damn fine!
Try adding some herbs (rosemary) or spices (cinnamon, star anise, cardamon pods) for an extra interesting flavour.
If you have room in the smoker, put in some peeled hard boiled eggs as they are delicious smoked. Or some cheese, delicious also. If I have any room left over, I always smoke some salt or chilli, which is great in cooking.