Replace the player.mdl file in the models folder with the model you want, simply done by overwriting it with a new file of the same name if one exists, if it doesn't place a new one anyway. It still works. Any model set for a player model, such as deathmatch player models, ones from other mods, or custom made ones even, will work just fine.
Also, sorry no one helped you with this earlier. I now just noticed it myself. There is no need to post a new post to bump. Near your avatar, a small EDIT link is available if you were the last person to post in that thread. Editing also bumps the thread. A thread will be locked after 90 days of zero activity.