How to hide a list in Designer:
In List settings-> General Settings
1) Uncheck option “Display this list on quick launch”. [This is necessary]
2) Check the “Hide from browser”.
3) Save the list.
Open it SharePoint site in browser and check that your list is hidden now.
How to open hidden list and unhide it in Designer:
1) Open SharePoint designer 2010.
2) Click the “All Files” folder at the bottom in left pane.
3) Right click your hidden list from “All Files -> Lists” folder and choose property.
4) Now you have your hidden list open in SPD.
5) In List settings-> General Settings: Uncheck the “Hide from browser” and save.
aanuwizard.com 
Unhiding it could be tricky. Thanks for blogging this.
I was trying to figure out the unhide part. Thanks for the blog!
Pete
Any reason why I would not see All Files in Designer?
Never mind, I figured it out. Thanks for the blog post!
I also cannot see All Files in Designer. What did you do to fix this?
I have the same issue, I cannot see “All Files”. Please advise. Thanks
1 question pleaze. OK with hidding the list. After updating the list by addinn records, using an Infopath form i created, the list pops up….can you help me on that?
Where is the “All Files” Folder??
Nice Post 🙂 Thanks
Since some people have asked this. The way to unhide is to go to the external content type, highlight the list, click the Go To List button from the ribbon. From there, you get the standard SP list edit form, where you can unhide the list.
Looking at the list in All Files won’t allow you go do this.
how to unide List in Sharepoint designer 2007?