Hi, Ive got one of these and it holds my 5dmk2 with 24-105 pretty solid. Highly recommended.
Manfrotto 709B Mini Table Top Tripod
That little Manfrotto is awesome... and it fits in your jeans pocket. The legs don't extend... but you will become skilled at spotting rocks, stumps, railings and stuff to put your camera on. It's solid metal, and built strong.
But I actually like the Giottos version better. The Manfrotto will hold 4.5lbs, while the Giottos will hold 7lbs, which is enough to support a 5D + 70-200 f/4 in light wind.
Legs only: $25 (supports 11lbs)http://www.bhphotovideo.com/c/product/512856-REG/Giottos_QU500B_QU_500B_Mini_Tabletop.html
All Metal Ball Head: +$20 (supports 7lbs)http://www.bhphotovideo.com/c/product/490023-REG/Giottos_MH1304_110C_MH_1304_Pro_Series_II.html
All Metal Ball Head w/ Quick release: $35http://www.bhphotovideo.com/c/product/527934-REG/Giottos_MH1104_330C_MH_1104_Pro_Series_II.html
You probably don't need the quick release... it's so small, I just leave the tripod attached to the camera.
... Don't expect miracles, though. I've traveled the world with my gear and tried practically every mini tripod that's been made. This is the best compromise between size and stability - at any price. And bonus! It's under $50. It won't come close to working as well as a full-sized tripod... but my 'real' tripod is 7lbs and >$300... and it sits in my closet mostly. My little Manfrotto goes mountain climbing!