Luring a wild cat

I had a female tame prego mommy unload under my house. Nothing like low crawling under your house with a flashlight and a shoe box at 4:00 AM trying to find the wailing lost kitten. I grabbed it (about 2-3 weeks old) and played with it until 0600 then I let it go because mommy came snooping around with a scared look on her face. I didnt know there were 3 more under there. After about 2 weeks of watching them eat food I put out for them with a webcam I put in the crawlspace, I got a little closer to them and when all 4 were out of the crawlspace, I slammed the door shut on them and they all bolted into a penned off area at the open end of the dog run except 1 that went the other way and hid under a 5 foot tall woodpile. for 20 minutes I chucked about 1/2 a cord of wood over the fence looking for this little black kitty. Found it and grabbed it by its nap but the little **** turned on my hand and bit me! so now Im running with this kitten attached to my finger and I end up flinging it into the pen. The other 2 went for the other intrance but I put a cinder block in front of it so they both hid in the 2 cavities. I just blocked the front of the block off and picked it up and put it in the pen, the 2 kitties never got out. So now I have 4 ferile kittens in the pen along with mommy. Everyones happy but me becasue I know I have to get rid of them. I get mommy and the kittens in 2 large boxes but one gets out and I chase it all over thy yard until I throw my shirt over it and pick him up in it. Now Im a little pissed and winded, so I haul them off to the shelter. I later heard that it was a "high kill" shelter and the wild kittens were probably gassed before I got home :-( Mommy made it on their website and was surely adopted.
So....maybe you could rig up a trap in this manner: If its a small cat that cant really jump yet, get a box with the end cut off, put some food at the other end and hang it off the edge of a table over a trash can. When the cat goes in to get the food, itll tip off the table into the trash can and maybe you can rig the top to close. Throwing a towel over one allows you to pick it up without getting rabies....