You can change this architecture and you should probably change the navigation model.
Users usually don't have that patience to go through 6-7 levels of navigation to find an item. In such cases these can be helpful :
Try recategorizing the items in order to organize them in at most 3-4 levels(depth), which means after 3 or 4 clicks, users find the item they want.
Try relisting the items. That is if you have something like "Baby clothes" you should list it in "Baby" category and also in "Clothes" category.
Searching for a specific item through these many levels is obviously really hard for users. If the user knows exactly what she wants so a search box in the top of the page can be more of help. The user searches for the item and they find it! But if they don't know exactly what they want and they wanna observe similar products or wanna browse through the products in a category, then making the categories smaller and increasing the levels of categorizing can be even more confusing and not helping. So it's better to merge some categories to make bigger groups of products that are similar to each other, and make it easier for the user to browse and remember the path she followed to reach the item. Also you can use featuring the items in order to make the browsing more specific without increasing the depth of browsing for users.
You can Also change the way you show the navigation to the user. If you're designing for a website, then you can always use a side navigation (like what you did in your mockups) but with a little bit of change. When clicking on a category, you can open the children of that category underneath them so the user will see which choices they have if they go into that category (or folder). Like what you see in the navigation Macy's use :
You can Also use a navigation on the top of the website (under the header), because that's where e-commerce websites usually place it and so users have got used to see it there, again, you can see the example in the picture above from Macy's. This kind of navigation can be opened on hover or click so the user can see what's under a specific category they're about to view without really going there, so if it's not where they wanna go, they don't have to click the back button.