At Blackpool Pleasure Beach they have 2 Beacons on the 2 tallest Pepsi Max drops (213' and about 179' I think) so it is possible to attatch them to the coaster tracks, its just not always a safe option, as am sure someone has lost an arm on the PM as you get so damn close to the light
http://www.rcdb.com/ig775.htm?picture=24 You can see it in this picture.
Also the park has a 180' drop tower (Ice Blast) and it doesnt have a beacon, so your theories of them putting the beacons on the towers isn't the case.
And while a beacon isnt the nicest looking thing to have on an attraction, would it really be the end of the world if it was there. Theres millions of ways to disguise it, a flagpole or something.