Although it is a topic of May, but .....
Yes it is possible. As other has says, much depends on the server parameters.
As for the SilverStripe...
I'm finishing large project on na SilverStripe. I migrate a large service from Joomla 1.0 to SilverStripe.
Database have 3,900 articles (41 mln characters) in 19 nodes. I developed a method which shortnes long nodes and this was solved many,many performance problems - in /admin and live page. All from 3,900 items are avaliable to readers.
Homepage takes about 70-100 items and this was generated and send by Firebug 1,2-2,1secound (with no StaticPublisher) and 80-130ms with StaticPublisher, with no static files (js,jpg).
I developed and use incremental generation of cache site with the possibility to generate any page (without start /dev/buildcache because server has one limit - max_execution_time = 30)
And now the best - the database was scaled to 12,000 articles (750MB!!!) and SilverStripe behaved stably.
Service out of about 3,000 visits per day unique users. During the day, generate 6,000-9,000 pages.
The project is build on SilverStripe 2.4.2 and in last week upgrade in 2.4.3.
Probably the site will start before the end of the year. Perhaps the address placed in the showcase.
if anyone had any questions as we did - we hint
My email: firstname.lastname@example.org
P.S.Once again - sorry for grammar :)