Wouldn't the easiest fix be to simply create 'in-between' tiles? For example, if you're making a 32px tile, you make 16px margins, creating a 32px tile out of the two margins.
That would work as a holdover solution, but it would still be ideal to have a better way built into Sprytile. I'm working on a huge refactor of the code so this might be addressed sooner rather than later.
