Drop Handlebars on an Old Bike
You can have mudguards and a chainguard, mudguards and drop bars, but not drop bars and a chainguard:

http://sheldonbrown.com/retroraleighs/

To use an automotive analogy, you are looking for the station-wagon version of a two-seater sports car.

That said, why not put drops on an old Raleigh 3-speed? The 3-speed Sturmey Archer lever will be simple enough to mount, you will just need new bars, levers, all-important bar-end plugs and tape. Obviously the bars will need to be the older 25.4mm clamp size, but you should be able to acquire these bits and bobs second hand for not much money. The alternative option of getting a chainguard to put on a retro Raleigh is a bit harder - those were a bit model specific whereas handlebars are not.

Personally I have a 12 speed Raleigh Gran Sport with the drop bars and a Raleigh Sports 3 Speed with the 'Northroad' bars. I would not swap the bars over on either because they are well thought out and go with the frame geometry. The 'Northroads' bars are a real treat and, if I did not already have a 3-speed with them, I would look for a bike with them.