I wonder if such a thing exists? A purpose built float rod that heavy I mean.
I do float fish sometimes for carp which can run quite large. I use a barbel rod of 1.7lb bs .
Its old hat now but my JW 11/13 ft barbel rod can handle carp and can tolerably cast a heavy float on 10lb line if the distance is somewhat limited which is fine for margin stuff.
Maybe the required length could be a problem with that although the poster has not said why one needs to be that long.
A 1.5 avon would certainly cope. Wasnt the old Redmire record extracted on a 1.5 rod?
Look to the brands best known for carp/specialist stuff. As well as the Harrisons mentioned by Squimp, they also do GTi SU/2xSU float rods that are worth a look. FreeSpirit also do (have done) rather powerful specialist float rods. I have an old discontinued model that is labelled as being 1lb 6oz TC. It's an absolute animal, built for float fishing for animals. It's of very little use if the fish are much less than 10lb. Current FreeSpirit rods that may be worth looking at would include the Hi-S Special Power Float and the Tamer Power Float (though the descriptions don't make them sound as powerful as the old rods I'm familiar with).