C'mon now JD, we all know you're asking this question, just to rub in the fact that you're solidly in the 11's...
And a big congrats to you for having done so!
As for running in the 1/8 mile, ie our track at Sealy, "NO", they won't require you to have a cage. They are so lienient there, that they only require us to turn in a tech card, w/o the car even being looked at, as long as it's not a monster race car, dragster, etc.
However, as we both know, our 1/4 track in Baytown really picks on these old sedans, (yet while turning a blind eye to the LS1 Corvettes and F-Bodies running the same). Keep in mind though, their inspection also has a relative amount of grace. If the old woman at the Timeslip booth sees a cage in the car, she's not going to look to see if the rear hoop bar is welded. Whether right or wrong, she (and others) don't look that maticulously, unless you go rip off sub-11 second ET's with high mph.
If/when I put a cage in mine, I plan on bolting the rear hoop bar in, using proper strength bolts (grade 8 or better), and if somewhere down the line I get scolded for it, I'll address it then. I'm like you, in that, I don't want to give up the back seat usage either, and I don't want it to only exist for smurf-size people.
Let's discuss this in person next time we grab a bite, and I'll try to give you some names you can talk with locally that have faced this dilema, and how they got around it.