So I am considering migrating once of my sites which I developed back in 2000 (CUSTOM CMS) to Moveable Type. I am wondering how hard it would be to migrate mygamer.com to it. I have considered Wordpress and other CMS packages like VIVVO (Which I purchased a dev license but decided against it since the plugin communitty is almost dead).
Please take into consideration the site would be platform / game based.
For instance:
The game page:
http://www.mygamer.com/index.php?id=555834&page=gameportal&mode=gameinfo
Which links out to other items like Developers / publishers / previews and the like...
WOuld this be a nightmare import?
Reported on Movable Type 5

I don't see why it would. What you'd need to do is write a utility to generate a Movable Type export file from your posts and then create Movable Type templates for your look and feel.
Indeed, I've done this a couple of times for other projects. Writing a perl (or other language) script to extract content into MT export format is the best way to go. The format is documented here: http://www.movabletype.org/documentation/appendices/import-export-format.html
Don't hesitate to contact me if you need professional help with this ;-)
I have written a number of scripts to scrape content from pages, be it MT-driven or just plain HTML. As long as it is well-formatted, you are usually fine. Then you take the import file and import it into MT and you are all set.