I've never done it myself, no. Once you take the top valve/spear out of the keg, it's just a wide open vessel with a skinny neck just like a carboy. If you feel confident you can get it clean (why not), go ahead and siphon the beer in. Now, the trickier part might be sanitizing the spear/valve assembly. I've taken these apart as well, just messing around. I suspect sitting it upside down in a small bucket of sanitizer will clean the externals. You might want to fill the keg with 1 gallon of sanitizer, insert the spear, attach the tap, pressurize and dispense the sanitier out. This will clean the inside of the spear, valve and the tap internals. If I really wanted to stick with sanke taps only, I'd go for it.
So far, I've only tapped sanke kegs on a short term basis for a party and I transfered any leftovers directly into a 5 gallon corny. People think a 1/2 keg of beer is so much cheaper than bottles but it's really not when you return the keg with over half the beer left.