That is possible and the easiness depends on your hardware. If you have lots or RAM you can run 10, 20 or 50 virtual machines each with an instance of your application making it 'multithreaded'.
OR you can use a portable version of IE and run an instance of it in each thread. This also lets you automate other portable browser versions like FF, Opera and so on. But naturally it is more hassle.
Well we can get 1000 captchas for ~$2. I gave it a thought and saw a potential. Currently I am paying $40 for 1000 manual comments and it is working great (I guess I could go lower but I prefer happy employees). The success ratio is way beyond any auto poster I've seen or created. Now 1000 may not seem like much but a lot of people forget that backlinks work best when coming from different domains.
The day I wrote that it is better to outsource the commenting and sell the autoposter itself I was cleaning up RSS pings I monitor day and night. Out of 200 000 000 submitted urls there were approx. 800 000 unique domains, 320 000 of them were blogs.
150 000 were open for commenting, the rest were just splogs. No more than 20 000 had a PR above 5. These blogs were hosted on at least 7 different platforms, each with all kinds of spam protection.
Now instead of battling javascripts and trying to solve math question and what not with code, I rather spend tax deductible $800 and get a substantial amount of BLs form high PR unique domains.
If you still think it is ridiculous, well, who am I to change your thoughts