Its been said that you can use black grain filler for Pop.. and I've also see that ash will give some Snap to the tone. I'm thinking... if you just twisted the wiring to the pots, you'd have plenty of Krackle too. At that point, just add some milk, a little sugar if you like, maybe some sliced strawberries and/or bananas. I'm saying all this, because Telecasters aren't just for breakfast any more, but ya know... they're still best that way.
I'd mix up black and brown grain filler in about a 1-3 ratio black to brown. That will give you a very dark chocolate color. Fill, and fill and fill and fill... until its smooth as a the inside of yer girlfriends thigh. Then you can clear coat it (the Tele, not the thigh) with lacquer du jour (Deft or Cabot, or... whoevers). If its not "amber" enough like ash can be, a very light shot of Zinsser bullseye amber shellac RUBBED into the body with denatured alcohol on a tampon (yes, its called a tampon....for French polishing) - BEFORE the clear lacquer.
I just tried that with a USAC body. I used thet new Timber Mate walnut. Perfect color, but It sanded right out. Tied it three times, it sort of took. Not totally smooth, not what I shot for, but feels woodier this way, and still got the desired color effect. Actually prefere it this way. Followed it with three coats of Stew-Mac sealer and five of Stew-Mac satin nitro. Perfect. Now I need to "pop" the flames on the Warmoth neck I have for it. Many, many flames, but in dire need of "stain popping", I guess you guys are calling it. Suggestions? I have some quite dark and aggressive looking ZAR brand stain. I might try that. It's oil based. Is that okay?