Is there such a thing as a battlefield commissioned officer these days?

No. The closest remaining equivalent is battlefield promotion for enlisted, but even then they already have to be boarded and promotable, so it's largely a ceremonial act for someone who was just waiting to make points anyway.

Battlefield commissions were an act of of desperation to replenish officer losses at a time that we couldn't keep vacancies filled. It's a good thing we don't have them. It means our officers aren't dying like flies.

I am going to make the strong assumption that it depends on the rate of attrition of LTs in war time.

Battlefield commissions or even reduced commissioning requirements only happen during bad times. I imagine even in Vietnam it was rare and during my time commissioned, nurses commissioning only with associates has gone away. Now some branches have pathways from E8 to CW2 and even O-3 but they are not battlefield. I know a Coastie that just went from E8 to CW2 which is commissioned.