Allow customers to modify their design in their account

Hello, 

First of all, thanks for this great plugin what I use for my business. 

I come to you with an idea :

Allow custommers to modify the design of the current order 'till the order is completed ! Sometimes, my clients fail their design and I have to modify it and it's uncomfortable to receive all those files via email. It will easily be difficult, and I can lost all the attachments of my customers.

As you already give the possibility to view the customized product after order, could it be possible to allow to send a new version of this design in the order ? 

Thanks

(Sorry for my english)