wrote

Suppose I have a rig with two VFOs. I'm hunt-and-pouncing
QSOs on one frequency and listening to the pile on VY1JA
on another frequency on the same band. I toss my call at
VY1JA at appropriate moments. Is that SO2R or not?

No. At best it's SO1.5R.

The line has to be drawn somewhere.

The line has already be drawn --- SO. The purists maintain that whatever an SO
can do to improve his ability to run up a score should be allowed. I'm inclined
to agree.

The difference (to me, anyway) is that multiband SO2R
essentially takes two complete stations capable of
simultaneous operation even if they're
both not in transmit mode at the same moment.
That's where the line is - for me.

Would you draw additional lines at SO3R, SO4R, SO5R, etc?

OTOH, it could be argued that as long as there is only one
signal actually transmitted at any given time, and only one
operator, there's only one "station", regardless of how
much hardware is involved.

Seems like a good argument to me!

Now for a topic in the opposite direction: How about an "Iron"
category (as in "Iron Chef" or "Ironman", etc.).

One rig at a time, only. No second VFO, receivers or memories.
No computer logging. No memory keyers for voice or code. 150
W maximum power.

I wouldn't be in favor of such a category. To me, one of the attractions of
radiosport is that it encourages pushing the limits (within good ethics) and
thinking outside the box on several levels: innovative station design, battle
strategy, skill development, and taking advantage of every available technology.
Your "Iron" category seems like putting hobbles on Secretariat in the Preakness.
Diana Moon Glompers, the General Handicapper, would love the category! (Think
KVG/HB)

73, de Hans, K0HB