This research is a few years old but, hopefully, things should be even better by now: http://www.boutell.com/newfaq/misc/urllength.html .. Safari, Opera, and Firefox all go over 80k. I found another source for Chrome that says they "could not find any limits on Chrome and Safari".

Nonetheless, it's tricky because you have no idea if proxies in the middle will be able to cope, mobile clients, and all sorts of things.. so you're right in the sense that it's pointless (if you want it to be universally acceptable ;-)).