Not even near but I just (yesterday) created nearly 200 pages and my observations...
After about 100 th page I realized that creating and savin page of panel is becoming a bit slower. Respond time on my server increase from 1 second to 3 second on my last pages.
Not about a change in connection performance.
But thats great for me cos it was about 40 seconds in my bygone CMS :C
I learned some...
1. Do not thick on the drag and drop feature except times you need. Got a bit of effect.
2. Core features and browsing in panel dosent change. But my DB is still small cos Most of my created pages are waiting empty. When I fill them (in a week) DB will be more than 30 MB and I'll see. But experiences up to here, I belive that SS will keep moving in condition.
3. First create the pages and turn back again to fill them. Trying to do it in one step seems taking more time and needs more attention.
4. Now this is quite important.
Start creating site tree from down. I mean from your last (menu order) to beginning (top menu items)
Cos after about 10 main menu items (category) you start to need to scroll down and up in every page you build :D
But it is nice that the Drag n Drop menu tree on SS is quite stable and fast. also moves sub categories with without any error. So you also can start new categories in top then move them anywhere.
5. More than 1000 pages means tons of categories, cub cats and entries. Do not forget that some of templates eg BlackCandy (the default one) dosent support sub menus (in left pane) going more than 3 levels deep.
6. But it is nice that the same BlackCandy wraps the links on the top when they become too much.
Ok ok I'm sure you also know most of these :) but the first 4 item maybe takes your attention.