If one has been changing their oil reguarly, there shouldn't be any "sludge". With that said, I am in the camp that goes under the car. I don't follow the over night drain method, but I leave the drainplug out until the oil is at a very, very slow drip. Should there be any "sludge", I think the gravity and suction of oil pouring out of the pan is stronger than sucking it up through a tube. Also as mentioned, this gives you a chance to look around underneath.
For DTF, you can buy ramp extensions which would enable you to make use of your ramps. They are fairly common, and can be found at any Walmart or auto parts store.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section