onscreen keyboard enabled on:

http://www.google.ad/
http://www.google.ae/
http://www.google.am/
http://www.google.ba/
http://www.google.com.bh/
http://www.google.com.by/
http://www.google.cz/
http://www.google.com.eg/
http://www.google.fi/
http://www.google.hu/
http://www.google.co.il/
http://www.google.jo/
http://www.google.kg/
http://www.google.com.kw/
http://www.google.kz/
http://www.google.mn/
http://www.google.pl/
http://www.google.com.sa/
http://www.google.se/
http://www.google.si/
http://www.google.com.ua/
http://www.google.rs/

How does it manifest itself? Please post a screendump and/or means to invoke it.

I don't see it home pages but only on SERPs

I don't see it at all :-)

I've been able to see it on google.rs and google.gr only

You have to switch to localized and non-Latin language interface on these Google domain to see it :-)

I can see it too on google.co.il .

I see it now on http://www.google.ba

> You have to switch to localized and non-Latin language interface to see it.

This seems[sic!] to me a particularly limiting obstacle if I only want to insert a couple of non-default charset diacritical letters into a search term.

this greasemonkey script brings similar virtual keyboard on every site

http://userscripts.org/scripts/show/10974