Well, I'm already a developer & i'll use Jom Social to make the site looks like facebook & will install all the modules but the client wanted some customizations in it which need PHP developer
1 - to make many form for the profile like timeline like in facebook & normal shape so users can change
2 - Add an option for Pages like in facebook as Jom Social doesn't have & user also can change its form
3 - Users can change the form of the groups
4 - Users can change the form of homepage for the jom social
5 - Application related to the pages so users can use it to increase the site's fan pages like some sites do it for facebook page so when someone press on other pages he got bonus & he can increase his pages by this way
6 - add FBML option in pages
7 - users can Questions & links
This is a long time project & may need more upgrades if u succeeded in it & did all that in a short period
I'll not be restricted with you because i know it's a hard thing :)