nitto and BFG both make 275/60 drag radials now. BFG's been making them since 1995, nitto just started this summer.
I've tried both the 275/50 and the 275/60 and the 275/60's are superior for everything you want a drag radial to do: hook up and run big mph. A 28" tall drag radial is proven to be quicker and faster than a 26" tall drag radial in a stock motor TR. 275/60's can be launched harder and won't over rev the motor through the traps. A 26" slick might be slightly quicker than a 28" slick in the 1/8th mile, but drag radials aren't slicks. With drag radials, improved gear reduction is way less important than the ability to hook.
275/60's will raise the back of the car a little more than 1", but most stock spring TR's sag in back so they may restore the rear right height close to stock.
There will likely be some frame rubbing in hard corners with whatever 275 wide tire you chose, when using the stock wheels. This can be minimized aluminum brake drums or very thin wheel spacers. BFG 275/60's are shightly narrower than 275/50's so they may actually rub the frame less than the 50's, though they look much bigger.