I've had some limited luck in the past slotting attys and using them just like cartos in a carto-tank.
It seems there is some variance in the "wick" material used inside attys, and some worked better than others. By wick I don't mean the wick inside the coil, but the nickle-foam stuff (same material as the bridge) that runs around the ceramic cup of the atty. It was difficult accounting for the variance in that material, and if I put too big a slot in there it would flood like crazy. The sweet spot between flooding and dry hits was tiny compared to cartos, which is why I gave it up. Plus it was 5 bucks a pop instead of 1-2 for cartos.
If you really really like disposable attys it might be worth it fiddling around until you get it right. The slot goes where the cup is, not above in the chamber section. I tried using a punch and cracked the ceramic, so slowly running a triangular file over the tube until it just breaks through seemed to work best.
Have you ever tried a properly setup kayfun style atty? I know you say you can taste the wire and wick with rebuildables, but that sounds like some sort of setup issue. Seems a bit magical that the same wire and same wick material would cause some awful flavor in all rebuildables, but not be present in a disposable atty.
Thanks for the reply UncleChuck. The issues with cup cracking, slot placement, etc. are what I'm trying to avoid by hopefully talking someone into making an auto-feed atty that is pre punched or slotted in the right place and with a hole that's the right size.
I do have a Kayfun 3.1 and on occasion I have actually gotten a decent draw. More often rough hits from the cotton wick/microcoil and liquid leaking from the air hole. When it works it's a beeautiful thing but the thing is I don't like fiddling with wicks and coils. I like things to work all the time or at leat most of the time, not sometimes.