Does anyone know of a way to get a large joomla site transferred into K2?

I have made a run at this but, K2 seems to not fare well when pulling in 50k articles.

you might give k2 import tool at the bottom of this page
www.individual-it.net/Joomla/View-category.html
a try

Thanks.. Purchased, tried it. It doesn't seem to preserve the J category hierarchy.

It seems that many websites are having trouble importing content from Joomla to K2, as errors or white page.

I should import a few thousand articles to K2 v2.5.7 from Joomla 2.5.6, but the import function in K2 only managed only two thousand articles before it got error messages and everything stopped.

I consider this as a weakness with K2, "the powerful content extensions for Joomla", which are unable to import articles from the same Joomla installation.

Is there any possibility that JoomlaWorks in the near future improves the import function?

Here is the error message I got:

Notice: Trying to get property of non-object in /home/2/f/xxxxxxx/www/administrator/components/com_k2/models/items.php on line 1024

Notice: Trying to get property of non-object in /home/2/f/xxxxxxx/www/administrator/components/com_k2/models/items.php on line 1024

Notice: Trying to get property of non-object in /home/2/f/xxxxxxx/www/administrator/components/com_k2/models/items.php on line 1024

Fatal error: Maximum execution time of 60 seconds exceeded in /home/2/f/xxxxxxx/www/libraries/joomla/utilities/arrayhelper.php on line 255

Maybe you need more resources on your host to complete this operation? it's a two-way street...

You might also wanna try disabling both Joomla's and K2's Smart Search plugins and try again...
...for me saving category settings would fail when Smart Search for K2 was enabled...so try disabling it before you import content from Joomla