Drupal search - 2 search pages using their own settings
First, I would consider to use Views along with exposed filters to create your special "search" pages. E.g. create a view which only lists blog entries and then add a filter for body text to it.

My next approach would be the Search API module along with the Search API Page module.

Last but not least, you always can write a module for that. ;) I would take a look at different search modules which already implement additional search pages.