in the future you might want to sell it with them dirt splatter on a seperate layer and have a psd, and xcf file so gimp users could use it to. just a suggestion.
More off topic, but does dexsoft happen to be looking for anymore members?
Gimp can also read PSD so XCF is not needed. But yes, this would be possible. Maybe I check this out with the upcoming pack I already work on.
And yes, we always are looking for new packs and new talents.