dirkington

Maybe look at

http://www.tipsandtricks-hq.com/query-or-show-a-specific-post-in-wordpress-php-code-example-44

You’d probably want to exclude each post from your index too I’m guessing.
Id have a specific category for projects and exclude the entire category if it were me.
http://codex.wordpress.org/The_Loop#Exclude_Posts_From_Some_Category

For your main problem I would have two specific categories. One for each client and then put the posts from either category on their own pages. But you can always have one category and include specific posts from the category on your page, but you would always have to exclude them from wherever else you don’t want them to be seen.

I didn’t see that link before. Honestly, you could just use Twenty Twelve. Your site is simple enough to where you could make it work. You might need to move some things around, and change the look slightly, but all and all it’ll work. I think. Just my opinion.