How to say when a university was established Chinese universities can use  建立于1926年 or 创立于1926年 or 创办于1926年to say "established in 1926." Are there significant differences between these?  

Also, is there any standard short form comparable to the English abbreviation "est. 1926"?

Searching on Google shows the various options described in the comment and the answer are almost equally common, both in connection with 大学 and without that.  The results seem to be heavily influenced by machine translated web pages, so may not be reliable. 

What stood out to me was that results for 创立 immediately gave much more reference to prestige universities than others I tried. That may just be chance.  But Siyi Deng also suggested this was the most prestigious--and prestige is the point of anything to do with trademarking.
创建于

建立于

创立于

创办于

are all acceptable, but for university I believe 创立于 is the most accurate one, the 立 here adds a subtle preeminence hint, and the 创 implies hard working.

In contrast, 创办于 does not have the "greatness" flavor, and 建立于 can be used for any institute in general.

I don't think there is an abbreviation that can convey the same implications.