1. Yes, several portals, each I believe you could do with what you want, you should checkout vBadvacned.com and coreforums.net
2. Me and my team (just the two of us right now) have developed uCS, I am not sure how it compares to IPStore though. However, it gives points per thread, per reply, per threadview (to the original owner) as well as each forum has a multipler to allow further customization

. PAssword to forums, upgrade member ship are part of the default package.
3. I've never heard this, to be honest, Ive never seen a HUGE IPB site (5+ million posts) but there are sites that run vB with larger stats than 5 million
4. I've not used any

so i have no comment, you might want to checkout photopost, and i think vBadvaced's team is developing one as well.
5. Yes and no, there is one, its in beta IIRC and it can be very server intensive if tuned wrongly
6. Raider soft has a vB intergration, there are also a few IRC intergrations.
7. Dont think so at least not now.
8. phpadsnews seems to be very popuar