My younger brother is in the same predicament. He's had his CT into MP for over a year, and has not even gotten on an MPAC yet. As for our Attrition rates slowing down... perhaps across the board it's looking that way, but for the detachments around my area ( 1 MP Regt ) it seems we are always undermanned. At the field platoon however, we seem to be at full strength, something that this area hasn't seen in years.
We have lost a quite a few qualified MP's over the last few years to civillian police forces however, and other bases I've visited on tasking or otherwise seem to be feeling it. The trade may be green, but since it is a trade with such a transferrable skill set, I can see that "green" status not lasting for long... I could always be wrong though, especially with the defense budget cuts and an uncertain economy, people may be more inclined to sign on past the VIE.
As for my brother, he's currently switched his CT/OT over to MSE Op in the hopes of eventually transferring over to MP. He understands that he will probably at the minimum have to serve out his VIE as an MSE and realises that he may never even get the chance to OT again. Best hopes for him, and the rest of you trying to get in trade. Don't let it get you down, keep on persevering if this is the route you really want to go.
For those of you that want to do policing as a career, please take note that life as an MP can be exciting, rewarding and busy. Even on the "busy" bases though you probably will not see the call volume you would working as a civillian police officer. Of course, with us being MILITARY Police, you could also one day find yourself in a field pl, and sooner in your career than you could guess. When I transferred from Res Sig Op to Reg MP in 2010, I thought my days in combats driving around big green vehicles were over... I was incredibly wrong
Don't let that discourage you though, because as always the grass isn't always greener on the other side. Both the Mp side and the mP side have there PITA moments a long with some really "good go's".
From one member who CT'd to others out there, good luck!