A few years back I used to floater fish for carp on a very regular basis, sometimes I would find you got takes just after your bait had hit the water, before it had popped up onto the surface. These takes were always violent - the carp seemingly very confident about taking a sunken dog mixer, usually it occurred when my bait (now I only ever use cork) had been waterlogged and so had very little bouyancy left.
After this happened a number of times it got me thinking and I developed a method that sounds like the one you mention, basically you feed plenty of mixers (or whatever bait youre using -bread is brilliant for this). You must find a nice straightish stick or use a peacock waggler, and attach this to your line at both ends with float rubbers, placing a no.4 or BB shot at each end of it for casting weight. Then on your hook/hair you have a similar (but sinking) bait to the ones you are feeding. For dog biscuits i used to use pellets, for bread obviously just use some flake. Start with your hooklength about 8 inches long, but the beauty of the stick is you can slide it up and down the line if necessary, let alone the fact it looks like a stick and not an obvious controller!
I used to catch a lot of fish this way, it works particularly well if they are being very wary of surface baits, showing interest in them but not really wanting to feed properly. Bites will show sometimes as your stick standing on end and disappearing, most often it will just zip across the surface of the water. Obviously your casting range is a tad limited but you can get it much further than you think, especially when you use a float/stick that can handle 4bb+ casting weight.
Not sure about the worms idea but I dont see why it wouldnt work, just that carp would be used to worms lying on the bottom of the lake rather than floating near the top - give it a go though mate!
Just out of interest, where do you surface fish for carp? (im from notts too /forum/smilies/smile_smiley.gif)