There is a reason why the Title field is limited to 125 characters. This unfortunately could not be changed, since it is set in the database classes.
Most of the search take into account only the first 66 characters. To some other, this limit is up to 120 characters. For longer Titles, the web pages are considered as "advertising ones" and full with spam words in order to take the page rank up. For this reason, such pages are excluded from the indexes.
We do not want to encourage bad practices while developing with Sitefinity, that is why we put this limit.
I hope this helps.
the Telerik team