As a enlisted reserve Intel weenie (thanks for the term sailorgloom), I can let you know that I drill with SEVERAL people working on DIRCOM packages. I've never heard of a bigger group of enlisted people with degrees (some with advanced degrees). Great bunch of people - mostly highly motivated and intelligent (no pun intended).
With that said, I would think most DIRCOMs come from enlisted Reserves. I know of one person in the Intel training pipeline that was told if he wanted Intel as an officer he would be better off to enlist as an Intelligence Specialist (IS) and then submit the DIRCOM package (this was from an officer recruiter in Millington, not enlisted recruiter) The last numbers I saw on a DIRCOM website was 500 applications were looked at to fill 50 slots. It didn't break down the percentage of applications from enlisted or civilian.
Something to keep in mind if you think about the enlisted route. For Intel you have 8 months of weekend training before you start drilling with your unit. Being enlisted means you need your CO's approval to apply - this will take some time for them to "get to know you". If you are not prior service you will have boot camp and NPSAC classes as well. I would plan about 1 year before you are able to apply. (also figure in your security clearance - it's a help if you have that completed also - 12-18 months from enlisting)
But, enlisting as an IS will give you a leg up with the RIPO jerks... And give you a feel for what Intel does.