my playing cue right now is a cheap $10 Aska cue that's 22.5-23oz. it's weird because my other custom cues are about 19oz. it's actually my break cue but i realized how solid its maple shaft hit, so i changed the tip and now it's a player. 13.1mm btw.
I used a sneaky pete, drilled it out and added a tube filled with lead and as I recall strapped a bit of lead around the butt of the cue. I played with it for a couple of weeks and now I don't remember what I did with it. That was more than a few years ago. My Jump Break cue is the heaviest full size cue I currently have and it's a light 22 oz Mace by Rick Howard. My masse cue is 29oz.
A big biker dude handed me his cue to try out. After he let go, my arm immediately dropped. I wasn't expecting something so heavy. He said he filled the butt with metal shot. IIRC, it weighed 35oz. It wasn't just a gaffe cue. He played with it all season.
An Original Palmer Model #11 that (supposedly) once belonged to Joe Balsis.
It weighed 26 ozs. and came with 5 shafts. It was my favorite cue for 14.1, but
I got "stupid" one day and sold it for a bunch of money (which now is also gone).
I've held one of those 25 oz. break cues, but I own a 22 oz. Brunswick one-piece made between 1921 and 1925. It's very unique, having a full splice at both ends!
You can see it at http://sites.google.com/site/donnylutzpool/
The pics are the last ones, as you scroll down through the Cue Gallery.