Hi mate,
as Anglerben said above, there's really not any need for a 12ft carp rod/big pit reel for float fishing. Most carp rods aren't that well balanced as most of the time they are sat on rests so might be a bit tiring to hold for any length of time, especially with a big reel. A lighter balanced set up won't cost you any distance with float fishing.. in fact, it would probably increase it.
A 9/10ft spinning rod might suit you, with a 4000 size reel.. if the rod was rated upto, say, 40 or 50g, you could use it for lure fishing, float fishing, surface fishing with bread for mullet, and some light touch ledgering (holding the rod) for flatties and bass.
Because i don't do enough of that sort of fishing to warrant buying a rod specifically for it, i tend to use a 9ft carp stalking rod i already own for general close in stuff.. it's rated at 2.75lb tc which is a bit overkill for light stuff but it does a decent job for lobbing out small livebaits for bass under a sliding float, or with a 2 or 3oz lead and peeler down the edge of rocks. Stalking rods are usually quite well balanced as they are meant to be held.
You've got a lot of options really.