- You need to have some very frank discussions with either your Dell rep, or whomever is speccing out your quotes. $1k for corporate-level desktop PC in this day and age is ridiculous; you should be expecting to pay more like $600-700. To give you an idea, I work for a state university, and we're currently giving about $550 for a Core2 E8400/4Gig Ram/160gig HD HP. Integrated video and no monitor of course, but a 3 year warranty. Sure you're not going to be decoding the human genome with that machine but it's more than enough for your average office worker. Don't be afraid to use HP as a club against your Dell rep; they're currently getting hammered by HP in the corporate world, and won't want to lose your account, assuming you're of any kind of size. I wouldn't recommend going to HP unless you absolutely have to though; service is horrible.
- Take some time to consider whether the time spent building custom machines is really worth the time of whomever would be doing it. Chances are, it is not. Either you're going to have someone making peanuts doing the work, or a skilled IT person who really isn't all that interested in doing what essentially is grunt work. In either case, you're going to see problems.
- If you haven't already, you should discuss this with your purchasing department before moving forward. Depending on the level of beauracracy that is entrenched in your level of government, building your own computers may not even be permissable.
You mentioned that you couldn't find anyone doing this on a large scale, this should be a warning flag. Lot of potential problems and pitfalls here, not the least of which is your cunning "transfer the OEM licenses" plan. There are a lot of better ways to save money on computer purchases.