BTW for anyone lurking the problem with Jenn's link is that it's too long -- for her server, not for Marketo -- once the tracking token is appended. The tracking part works and redirects, but then her server says it can't load the URL.
This is really her webserver being misconfigured, since the URL is still short. I assume it has a really low limit of 256 characters!
An immediate fix is to turn off mkt_tok, although that's destructive because it means web sessions won't be associated. I'll be sending Jenn another workaround and if you're curious you could ping me as well.