I am sure there are plenty of MI jobs in the Ranger Reg's just like there is with FA slots. However, if you want to be kicking down doors with the Ranger's why don't you just go infantry. I mean in all honesty you will probably be detailed if you get MI to IN anyway.
I have a bunch of friends who are MI LT's with various units if you really want to know and I can direct you to them. What I can tell you from what they have told me is it's a lot of desk work so far int heir positions at least.