Just curious -- I have seen a 150 minute tape -- Were there any longer?

Yes, they went even further, there is such a thing as a TDK D180. Three hours from one cassette! Obviously uses extremely thin tape.

I just looked at a Youtube video of someone who has one, from it you can see that the tape is almost transparent!

http://www.youtube.com/watch?v=pnVbz8I0c3w

Wow, 180 that's pathetic.  I guess maybe it was used by people who only needed to record voice and weren't concerned with quality.

It was proberly more intended for things along the lines of Police interviews which can take a long time.

"tdk d180 normal type" surely there exists also the type ii?  

i imagine maybe they may have been a strain on the motors...i remember splicing two tapes together a few times back in the day in one casing...and it would struggle to turn sometimes....