Did you win the Emblem shown in your post? Is that for completing all challenges?

no

no ... I've got about 15 days to my name and only got about 3 guns to about the 400 headshot mark; 1000 Preds, 900 Harriers, 800 AC130's, gold on Last Stand & Silent. Thats the lot -- I'm miles off !!
"They" say you need all the Prestige Challenges and the Weapon gold challenges done. I have no idea how somebody goes about getting that emblem without boosting, or taking a genuine... x years , lol. Yes some people have got Gold on some weapons already, but it tends to be the easy ones; snipers and ump.
If you only had to get the killstreaks to 1,000 then maybe you'd get that in 25 or 30 days worth? But to get the headshots (which is what they rumours say you need), then it'll take an age. If there are 23 primary weapons (plus sheild) and you were to get 1 HS per minute (ie 10 per TDM game), then it would take you 16 days of play after you've gone past 1st prestige, and then I presume you have to complete the Sheild challenge too? Good Luck
Weapon list:
http://images3.wikia.nocookie.net/_...2/23/Weapons_of_MW2_(Primary)_RPD_and_FAL.jpg
And if you go by the Callofduty wikia, and maybe you need the secondary weapons too... then I'll be seeing your sign sometime next year.
"All Weapons - Assault Rifles, Submachine Guns, Sniper Rifles, Light Machine Guns, Machine Pistols, Handguns, Shotguns, Launchers (except Stinger)" can obtain Gold Skulls. But to get those too for the emblem would be harsh - no?