Thank you all! I needed to modify my search. It makes sense that they don't make 15 gallon buckets due to the weight placed on the handles but I do see a handle (what appears to be a flimsy plastic one at that) in the picture Duckfoot linked. After reading the posts that went along with the link, the handle worked well enough (I'll probably use a two wheel dolly though). Thanks again, I've found what I've been looking for!