Unresponsive contractors

Aaron and I have been trying to find a contractor to put in a patio in our backyard since early April. This has been one of the most frustrating projects we've ever undertaken, and no actual work has occured yet!

Contractor 1 showed up the first weekend in April, as scheduled. We had a written estimate from him emailed by the end of the weekend. So far, so good.
Contractor 2 did not show up. Three weeks later he called to try to reschedule, we didn't call back.
Contractor 3 showed up the middle of April, as scheduled. I had to call him to get our estimate, which he insisted on presenting in person in early May. When the estimate turned out to be 2.5x the amount of the first estimate, I sent him away, and he laughed at me and said that no one would do it for the price we wanted (which was bull, because we had Contractor 1's estimate).
Contractor 4 showed up in mid May, gave the yard a cursory glance, and gave us a very low, verbal estimate. Has not returned any subsequent calls.
Contractor 5 showed up in mid May, gave a detailed analysis, and promised to contact us with an estimate. We called several times, and received the estimate this week via fax. We have some questions, and our calls have not yet been returned.
Contractor 6 showed up in late May, and gave an extremely detailed analysis. He caught the fact that our porch is build on a over 6" deep concrete slab which cannot be removed. However, he works alone and cannot start until September. (Oy!) We have not heard back from him on price.

Contractors 2 and 3 are out. That leaves Contractors 1 and 4-6 to consider.
After much analysis, Aaron and I decided on slate. We told all the contractors that we wanted slate with varied results. Most have tried to dissuade us from slate in favor of pavers. I HATE pavers. I think that they would look silly with our old, brick house. I went on a garden tour of Frederick in mid-May, and saw dozens of beautiful slate patios. I want slate, dammit, and it's my patio. Contractor 6 was especially forceful about the pavers. He also addressed himself mostly to Aaron and not to me, which pisses me off.

So, what do we do? I'm kind of leaning toward Contractor 5. He was very professional, and his estimate was around the same as Contractor 1. I have tremendous concerns about Contractor 6 working by himself. Installing a slate patio by yourself doesn't sound like a fun job (or we would just do this ourselves). I don't like his September timeline either. However, our friends installed a patio themselves with the help of Contractor 6, and they've been enjoying it for weeks now. Theirs is made of brick pavers, and it looks really good. I'm embarrased to even contact Contractor 1 since he gave us his estimate over 2 months ago, and it's just asinine that we're still without a patio at this point. I don't understand why these people don't just call me back. I want to give you money to do something for me, I want to give you business, why not just call me back? Is my job that small? My business that unimportant? I just don't understand this business model that these people work towards, but it seems to be how all of these companies work. We'd appreciate hearing your thoughts in the comments section.