Heh, I love a challenge, so here's what I got:
The regular method:
Before the poison/AM bug kicked in, this is the highest I got:
I should have killed the AI at that moment, but the AM bugged let me go up to this point before the kill (which I don't consider valid, since it's a bug):
The vodoo method:
This is the best method I could think for getting the highest possible poison counter.
Before the virus/plague blow up:
And right after (my current record at 660 counters):
Decks used:
My deck
Hover over cards for details, click for permalink
80a 80a 80a 80a 80a 80i 80i 80i 80j 80j 80j 80j 80j 80j 7tg 7tg 7tg 7tg 7tg 7tg 52q 52q 52q 52q 74a 74a 74a 74a 74a 7ap 7ap 7ap 7q8 7q8 7q8 5rt 5rt 5rt 5rt 5rt 5rt 6rs 6rs 6rs 6rs 8ps
AI
Hover over cards for details, click for permalink
710 710 710 710 710 710 710 710 710 710 710 710 712 712 712 712 712 712 719 719 719 719 719 719 7am 7am 7am 7am 7am 7am 7tg 7um 7um 7um 8pn
There are ways to get a higher count than I did, since it's definitely possible to get vodoos to fill the last 3 open spots, as well as ways to deal some more poison before you need to set up the virus bomb, but enough is enough and I wasted too much time with this already.