Yeah, the community is not always super-quick to response to announcements.
Anyways, I think a comparison search engine would be great.
If you want, we can collaborate on the marketplace websites.
For my own search engine, http://bitcoogle.com
, I manually review each website before accepting it into the list of websites to be searched.
As such, I could provide you with a list of sites that would be beneficial for you to include in your comparisons.
My projects only assists with locating desired information, which is why I think your price-comparison search engine is a good idea.
I hope you find success