I believe that is a 1000.2 pan and arm with the 3 DishPro Dual LNBs. The conventional 1000.2 has the tripple wide LNB with integrated DPP Switch, which can feed 3 receivers (up to 6 dual tuners). If you already happened to have a DPP44 switch because you have 4 or more receivers, it is a good install. If you happened to have a DP34 switch it is a decent install but you would lose the ability to use a single wire run to a dual tuner receiver (with the separator).
The original 1000 could also use 3 DishPro Dual LNBs, but I think the arm is a bit shorter and the "W" adapter holds the LNBs closer to each other.
Yes, a 34 switch can be trunked off of a DPP44 switch as long as the original install was done right. Since we only got a picture of the dish I can't say for sure how you would go about doing it, but most likely you would run 3 short RG-6 lines from the right side of the DPP44 switch ports 1,2, & 3, to the sat inputs of the DP34 switch. keep in mind that the DP34 switch does not have DPPlus technology, so if you install another dual tuner, you would either want to move one of your single tuner receivers to the DP34 switch, or run two cables (one for each tuner) from the dual tuner to the 34 switch. Also keep in mind that if the DPP44 switch loses it's power, you will lose signal on all receivers (including those hooked up to the 34 switch). Good luck