Thanks for the input everyone, I've enjoyed reading your responses. I have sent a message to dealer B to see if he is willing to match dealer A's price and still throw in the forks at dealer A's price without the forks. If he does, then I'll mention that to dealer A and see if they can do any better. Rather than try and guess whether dealer A is going to have hard feelings about me buying the tractor from dealer B and running service through dealer A, I'll just ask dealer A and factor in that answer.
I once paid extra to buy a riding mower from a local shop (not dealer A) thinking I'd be better off when it came to service and such, but it didn't work out that way. In a subsequent summer I spent two months without the mower while they addressed at the band-aid level, but did not fix, an issue that was covered under warranty. Later on another issue was covered under warranty but when it was time to pick up the machine they tried to charge me for it. Times that I brought in the machine they usually assumed it came from the big box store. That place is a bad shop, and it's not fair to dealer A for me to project that bad experience onto them, but from that I learned that the level of service after the sale might have more to do with the quality of the shop than the place I purchase from.