While shopping for some seeds at the terrific nursery section at Longs Drugs in Oakland, I came across packages of something called Gel 2 Root, little sealed cups of a patented rooting gel manufactured by Supa Plants in the U.K. I've never seen these before, but I had to give them a try. I got a box of two cups for $3.99; they also came in boxes of six for $12.99.
They couldn't make the process simpler. You prepare your cuttings the way you normally would, although there's no need to use any rooting hormone because there is hormone in the rooting gel. You poke a small hole for each stem in the foil lid and slide each cutting into the gel. Then put it in bright indirect light and wait for the roots to grow. You can see the roots growing through the clear plastic cup. (I also took the additional step of sealing each cup with cuttings into a ziploc bag, just to help the leaves retain more moisture.)
You don't need to water them--all the water and nutrients they need are in the gel. When the roots have grown sufficiently, you cut the foil lid open further to pull out the cuttings and transplant them. If a cutting doesn't root, you can replace it with a new cutting. (So says the label at any rate; I'm wondering if there would be any bacteria left behind by the old cutting that would contaminate the new one.)
I tried these tonight with salvia and catmint cuttings, both of which should root fairly easily. If these cups root cuttings faster and more efficiently than perlite or other rooting media, they might be worthwhile, at least for certain plants. But at two bucks a cup, that could get pricey if you have a lot of cuttings to root. Also, the package says they will not work with most acid-loving plants so that means azaleas and such need to be rooted the old-fashioned way. I'm really curious to see how well these work.