Generally speaking, two pounds is very lightweight duty. Heavy duty would be something that could mount a nice, sturdy gymbal head, a large fully-body camera (i.e. Canon 1D/Nikin D3), and a hefty telephoto lens (i.e. wide 600mm or 800mm). Such a setup could way a good 15-20 pounds or more, some ten times the weight your looking for. A tripod to handle 20 pounds would be pretty heavy itself, a couple/few pounds at least, plus maybe a pound or so for the gymbal head. Thats a lot of weight.

I have a Gitzo setup that uses the Gitzo GT0541 tripod and the Gitzo GH1780QR ball head. The tripod itself weighs in at a little over a pound, and the head weighs just under one pound. The tripod itself can handle 11 pounds worth of load, and the head can handle 22 pounds of load, so the setup can handle 11 pounds total. It works beautifully with my Canon 450D and 100-400mm Telephoto Zoom lens, which weighs about 4 pounds total. The mere two and a half pound weight of the tropod/head makes it a dream to hike around with, and it cost less than $700. Hooking some weight on the hook at the bottom of the tripod takes care of any instability (there is a little bit of give due to its lightweight construction.)

The above can be contrasted with the Gitzo GT5561SGT, a tripod designed for "heavy duty" work. It is capable of handling 55 pounds of load, weighs in at almost 8 pounds itself excluding any head (and its carbon fiber to boot!). The tripod itself costs almost $1300. Throw in a head capable of handling 45-55 pounds of load, and you tack on a couple more pounds, for a total cost of around $2000 or so. This puppy with a Wimberly gymbal head is capable of handling Canon's biggest lens, the 1200mm super telephoto, which weighs almost 40 pounds itself.

There are some middle ground tripods from various manufacturers that can handle load in the range of 25, 35, and 45 pounds. Sometimes, more than load limit, you need to look at how sturdy a tripod is. Lighter weight 'pods that can handle 11lb may be able to handle plenty of weight, but may just be too flimsy. A pod that is more rigid may be what your looking for, regardless of its load limit. Various tripod heads, including panning heads, ball heads, and gymbal heads exist for similar load ranges. It is important to note that the lowest weight capacity is the most you can handle, so putting a 45lb head on an 11lb tripod is useless, as you'll still only be able to handle 11lb worth of load.

Before you shell out any money on a "heavy duty" tripod (which could cost a small fortune), I would figure out the maximum weight of the equipment you wish to mount on it. Even a 500mm f/5.6 telephoto lens on a 1D/D3 type body still weighs considerably less than the 22-35lb load limit of most middle-ground tripods. Something like a Gitzo GT3531 @ $750, a good middle range 'pod, might offer you the sturdy build you need, even though it can support nearly 40lbs worth of weight (which is probably way more than you need.)