I had some success with short naps by waiting just outside the door ( or in my case - pram) and just as they are about to stir rocking, or placing hand on back etc - just to ease them into the next sleep cycle. The short naps tend to be because they are tired, so if you can extend them by any means possible, then do some early nights, they may well lengthen quite quickly.
H will still have short naps, especially after illness, but as he sleeps in his pram, I can normally rock him back to sleep and get another 45 minutes or so.
Regarding staying in the bed, in my experience, if you haven't mamaged to get them off again quite quickly ( which is why you have to get in there as soon as they stir) then I have never managed to get H back off at all, so I give up and aim for a super early bedtime!
I also envied those Mum's with good nappers! I spent the whole of last winter walking H to sleep in his pram twice a day! (Sometimes only as far as the end of the road - but still.....) I am just thankful we had a dry winter - paying for it now with bulging muscles form watering the garden with a watering can! LOL!