You do know that the 'waiting game' that dealerships use is one of the oldest tricks around. It is a delibrate strategy to frustrate you.
The idea is to wear you out as much as possible so when you get to the finance office you just sign anything put in front of you (that's the theory).
It is far better to go in with financing from a third party like you did. They are playing you right now by blaming Cap One. If you got financing from another outside source, they would have blamed them.
You are far better off not getting the dealership financing - there are all kinds of hidden fees F&I guys try to stick into the price when you go through dealer financing. Really take the time to read up on dealershp scams. You avoided that whole financing scam and that's why they are blaming Cap1. Congrats for not falling for the pressure. Congrats on the new car. 
@dballard17 wrote:Nice to know I got away with standing my ground! Hopefully....At least it seems like I'll be taking delivery of this vehicle. Won't know till Monday. The crappy part is that in 7 days the 10 day payoff on my trade is no longer good. I asked the dealer about that and he claimed they will easily get that taken care of on time. Really not leaning on his word though. Everything was negotiated and signed already, but I'm sure I'll hear something about me owing them money for putting more miles on the trade-in. They really didn't hesitate to deposit my 7500$ downpayment check though! With how this whole experience has been, I'm fully expecting to be told "The check didn't clear our bank so the deal is void, unless you want to come in try financing with us!"
You did your part. You performed. The clearance part of the check has nothing to do with you. It is dealership policy to allow the check to clear before they delivered the car to you - not some federal or local law. What do they think is going to happen with a Cap 1 check? Bounce? No. The dealer is just trying to give you a hard time. If they try to reopen the negotiations on the trade by paying less I wouldn't accept it. They are the one's that delayed the whole transaction (the dealer). Not you. Remember that if they come back with one more dime off the trade. If they start down the milage route, then remind them that you have been inconveienced by not getting delivery of the car when you paid for it.