The perks that you need are:

First Class:
Perk 1: One Man Army
Perk 2: Doesn't matter
Perk 3: Doesn't matter
Death Streak: Final Stand

Second Class:
Perk 1: Doesn't Matter
Perk 2: Doesn't matter
Perk 3: Last Stand
Death Streak: Final Stand

Procedure:
Select the first class mentioned above and have an enemy kill you four times so that your final stand death streak is activated. On the fifth kill, have the enemy put you into final stand. While in final stand, use One Man Army to switch to the second class listed above. When the classes change, allow your player to stand back up. From this point on, any kills that you get with the second class from above will count as a Last Stand kill. The only rule to this is that you can not change classes, and you can not die. If you do either of the two, you will have to start over from the beginning. This glitch does not, however, make kills count toward the prestige last stand kills, only the perk kills.

this does work. I got the last stand pro emblem today by doing this