If you are buying 1000 of them, I would expect the price to be *MUCH* cheaper than that.
I work for a local council - and my last PC refresh I got the PC and a 22" monitor from our supplier for just over $1K/system. I only ordered 60. All components come with 9-5/5 3 year warranty, got access to (thank godness) the ENGLISH HP Government Helpdesk.
I only need to do basic diagnosis of hardware faults - HD Dead, loud fans, PC/Monitor dead. We pay for warranty, we let our HP techs figure out the problem. One or two spare desktops is all we have ever needed.
I haven't crunched the numbers, but rolling your own is gunna cost you more down the track.
We also get our integrator to do the heavy lifting of swapping out desktops.