Well I finally reached level 55 and was awarded the Golden Desert Eagle last night. Now it's just a matter of finishing all the challenges, some of which are pretty difficult. For example: 150 head shots with all the sniper rifles. I'm not even sure that's doable with the current maps. Maybe if you were able to turn the kill cam off, but what this game needs a good sniper map. Something similar to the one that Greyfox made for Far Cry. Tall grass, mountains and tons of trees. That would be awesome!
Weapon challenges (150 head shots): From what I understand, when you complete all the weapon challenges in each category those weapons will turn to gold.
Assault Rifles:- M16: Done.
- AK47: Done (Gold).
- G3: Done.
- M4: Done.
- M14: Done.
- G36c: Done.
- MP44: Done.
Sub Machine Guns:- MP5: Done.
- Scorpion: Done.
- Mini-Uzi: Done (Gold).
- AK47u: Done.
- P90: Done.
Light Machine Guns:- M249 Saw: Done.
- RPD: Done.
- M60E4: Done (Gold).
Shot Guns (Only 100 head shots required):- W1200: Done.
- M1014: Done (Gold).
Sniper Rifles:- M40A3: Done.
- M21: Done.
- Dragunov: Done (Gold).
- R700: Done.
- Barrett .50 Cal: Done.