I made it, and it only redirects the pages you want to HTTPS and the rest to HTTP. You just need to keep the list up to date your self. And you can remove the '^/' bit if it doesn't work (my dev server didn't have those files in the root, but in a subdirectory, so I had to test without the '^/' bit anyway)
RewriteEngine on
#Domain redirect
RewriteCond %{HTTP_HOST} !^passwordmaker\.org$ [NC]
RewriteRule .* http://passwordmaker\.org%{REQUEST_URI} [L,R=301]
# Redirects to HTTPS
RewriteCond %{SERVER_PORT} 80
RewriteCond %{REQUEST_URI} ^/installation.html$ [OR]
RewriteCond %{REQUEST_URI} ^/installation2.html$ [OR]
RewriteCond %{REQUEST_URI} ^/passwordmaker.html$ [OR]
RewriteCond %{REQUEST_URI} ^/konfabulator.html$ [OR]
RewriteCond %{REQUEST_URI} ^/ie.html$
RewriteRule .* https://passwordmaker\.org%{REQUEST_URI} [L,R=301]
# Redirects the pages that shouldn't be HTTPS to HTTP
# Note the lack of [OR]
RewriteCond %{SERVER_PORT} !80
RewriteCond %{REQUEST_URI} !^/installation.html$
RewriteCond %{REQUEST_URI} !^/installation2.html$
RewriteCond %{REQUEST_URI} !^/passwordmaker.html$
RewriteCond %{REQUEST_URI} !^/konfabulator.html$
RewriteCond %{REQUEST_URI} !^/ie.html$
RewriteRule .* http://passwordmaker\.org%{REQUEST_URI} [L,R=301]