A Mini Site with a Site

Is this ok?

[uk_webber]

I have a large 'niche' site with one page on a particular very niche topic which gets the most search engine traffic after the index.htm by a long way!

The very niche topic KW is the second most popular KW in my logs and I am thinking I should capitalise on this popularity.

Therefore if I left the page in mysite.com/verynicheKW and developed a specially branded micro site around that page would that be better than refering all my traffic to a new domain name and site?

I am thinking it might be better to diversify and create a new site based on my success with this niche.

Thanks and hope this makes sense!