Since the basic problem is "dialup" vs. "normal" IP address,
the issue of static or dynamic doesn't really enter. Your IP
address is blocked and you want to solve the problem.

Yes, an SMTP server at the ISP (or, in my case, the dynamic-DNS
provider, who is not the same as the ISP) is one more thing to go
wrong, and at first I didn't like the idea since everything else
is in my house. However, the SMTP server has less downtime than
I do (and I have very little) and it is a "set it up and forget it"
type of thing. It's a lot less hassle than having, say, web pages
on another machine.

Any responsible SMTP relay server will not relay spam. My provider
will drop the connection if more than a normal amount of email
tries to be sent within a given time. This forces people to
correct the problem. (Presumably, when it happens, it is due to
a virus-infested PC.)

Despite my hatred of them, I doubt that spammers care if other people
get blacklisted when they do. They want their email to get out,
and though this bothers many people, they're not into bothering people
per se; it's just a side effec of spamming.