I think I've changed my mind. Since the quicklooklpugins depends on gimp.app it seems like a good idea to bundle it within the app. About the transparent: I think it's important to show transparency, no other ways to speed up to process?
ok, I tried: no-fonts and no-data real 0m7.651s user 0m5.816s sys 0m1.714s
no-fonts real 0m8.335s user 0m5.896s sys 0m1.792s
normal real 0m8.110s user 0m5.888s sys 0m1.757s
no-data: real 0m7.788s user 0m5.875s sys 0m1.715s
Just tried one run each with the same image and output parameters. I wonder what happen if we don't load fonts and there is a text layer in the xcf... I will have to test, 7.6 against 8.1s is not a great gain, but it's still that. I am not sure what the timeout is for the thumbnail generation, will have to ask the quicklook mailling list.
I was asking because it seemed like Auria was trying to compile it on Tiger. So I was thinking if so it's probably not worth the effort to fix it so it does compile under Tiger since it wont work there. In case anyone misunderstood I wasn't asking if there was going to be a Tiger version.