IMO, that's not a very smart design decision. Cost of maintenance is going to be much lower if you ditch one of the systems (*cough* wordpress *cough*) and roll everything into one system. That way, you don't have to find somebody that knows both Wordpress and Drupal.
Kind reminder that this is a support question and does not have to do
with development of Drupal. See http://drupal.org/community and
http://drupal.org/mailing-lists for more information.
Before posting search d.o for possible information.
http://drupal.org/search/apachesolr_multisitesearch/wordpress
--
Earnie
-- http://progw.com
-- http://www.for-my-kids.com