Looking for hosted Solr solutions I found also:

http://www.opensolr.com/

http://www.solrhq.com/

http://www.midwesternmac.com/services/hosted-solr-search

http://www.netaphorsearch.com/products/solr-hosting

http://www.acquia.com/products-services/acquia-network/cloud...

(they're mainly targeted to drupal)

anything else?

"also" = additional to the already cited websolr ;)

And there's also LucidWorks Cloud. http://www.lucidimagination.com/products/lucidworks-search-p...

Lucid Imagination is run by some of the most experienced Solr and Lucene devs. Specifically Yonik Seeley, who created Solr.