A modification of the Unacceptable and Acceptable techniques is a method based on the negotiation dynamic of purchasing a car. It goes something like this: you are sitting there in the car dealer showroom, having worked out all the major details (like model, price, color, options, delivery date, etc.). You pick up that magical pen as if ready to sign on the dotted line, then look up at the salesperson and say, "By the way, I assume you don't mind throwing in a set of those nice custom floor mats with the deal, right?" At which point the salesperson begins (again) to rant and rave about how much money s/he is already losing on this deal and how s/he cannot possibly afford to throw in the floor mats, which cost over $100 (retail, that is), which is more than s/he is even making on this entire deal. You calmly put down your pen, reply, "I'm sorry we couldn't make the deal happen," and head for the door (perhaps the third time you've done so that day). The salesperson stops you just before you get into your car, calls you back in, tells you s/he will give you the floor mats--for the discount price of $50. You get up to walk back out the door again. S/he stops you again and says, "All right, you can have the floor mats!" (which cost the dealership no more than $20). S/he gives you the pen, you sign, s/he gets the sale, and you get your floor mats for free.
Great, you say, now I know how to get another $100 thrown in when I go to buy my next car—but what does this have to do with job offer negotiation? Simple. Even though the deal was already "closed" it was still possible to get one more minor concession. The same thing applies to job offers. The only difference is that you don't have to walk out of the showroom and your new boss probably won't be ranting and raving like a lunatic car salesperson. You simply present a minor (it must be minor) negotiating factor in the "By the way, I assume _____, right?" format as if you assume it's okay. Examples:
"By the way, I assume my taking a week to spend with my family in Tennessee before starting would be okay, right?"
"By the way, I assume the plans that my family has made for vacationing at Disney World in late August won't be a problem, right?"
"By the way, I assume that my mobile phone expense while on the road will be covered, right?"
Please take note: the only way this approach is "no risk" is if you are willing to give in, no matter if their response is yes or no. Because even though the buyer was on his/her way out of the showroom over some stupid floor mats, s/he always would have gone back in and signed, even if they didn't go get him (s/he didn't want to start all over again, either). Sure, it's a fun way to play a final bluff. But you will almost always get the floor mats—they almost always give in. Why? Because the cost of the floor mats is insignificant in comparison to the overall deal. So make sure it's insignificant and be ready to back off if your bluff is called.
But even if you get a "we can't do that" response, they will usually feel guilty that they couldn't and may even offer other concessions in exchange. This negotiating stuff sure is fun, right? Yes, it sure is—just don't get carried away. It is truly a once-in-a-job opportunity.