Aside from a local studio for custom commissioned pieces, I have no problem using Audiojungle, or even the cheaper alternative with an Envato Elements subscription. Obviously you have more chance that people will hear the piece used elsewhere but it all depends on the client and budget doesn't it?
Thanks for the suggestions. We've gotten used to having access to stems and/or mix variations which allows for a little more control over texture and can provide some variety. Smartsound's approach looks interesting. I did a quick search on Audio Jungle/Envato but didn't see any alternate tracks that weren't just different lengths.