I have a client site built with Classic ASP techonolgy. I'm trying to determine what my options are for a blog for his site. The host does not offer anything. The client definitely wants the blog to be integrated into the site.

Use Wordpress domain mapping, so the site would be blog.clientsite.com even though the "Real" blog would be at clientsite.wordpress.com
PROBLEM WITH THIS OPTION: we would have to use a Wordpress template - so it would not looks the same as the client site - so this isn't an option unfortunately.

Get a new host - maybe Wordpress.
PROBLEM WITH THIS OPTION: We would have to migrate the existing site to a new host, and update all the ASP code to PHP - this would take more time, and cost more money for the client, but it is an option

Find some kind of blogging software that would could use on his site - like some kind of off-the-shelf classic ASP (or even .net) software that can be installed to www.clientsite.com/blog

OPTION 4: you tell me...?

Does anyone have an ideas? Suggestions, warnings, concerns?

Thanks in advance!

i had to integrate a blog for a friend who's site only allowed html, javascript, and css.
i used tumblr, its easy to integrate and totally customizable. it can be customised to match ur clients site. just search it on google how to style it.