I'll be spending a few hours in Queenstown but not the night. Anyone know of places to store luggage for a few hours? Thanks.

Are you just flying in and out?
If so you might be able to arrange an early check in, and if No to both, then what transport are you using or if flying in and out and unable to check it in early or want a later access, if you are using a shuttle, I'd have a yarn to the driver and if they cannot arrange it at their depot or even keep it with the shuttle, they'll be able to suggest somewhere.
All else fails, I usually hunt out a quieter looking shop and just ask, offering to pay $5 and quite often if you've come across a friendly proprietor and are prepared to have a chat for a few minutes, it'll more than likely ending up being for free.

No but he is just looking for somewhere to store luggage for a few hours and they may be able to oblige.
If he is using Intercity who use the Visitor Information Centre as their pick up point, and they can not oblige there and Busnz aren't interested then it's back to finding some friendly business.
And don't let me stop you coming up with a suitable option either.
I do not know of places to store luggage in Queenstown, and so I am not offering any. What I do know is that neither of the major bus companies have any sort of depot in Queenstown, just a bus stop (even the Intercity) and thus will not be storing luggage for him. I don't want to send the fellow off on a wild goose chase after non-existent bus depots, or to any other place I don't actually know there to be some way of storing luggage. I'd suggest you adopt the same policy. Sending him to a charter bus outfit to store his luggage is plain crazy. Your best suggestion is probably that he simply ask at the Visitor Information Cenrtre, even though you don't actually make that suggestion as such.