Just some things to think about.
Time is money - call the local screen printers. Work out a deal with them. Let them know that you'll be back again and again (if things work out). I have a guy 20 minutes from me that screenprints - he charges me 15% less than a normal customer, gives me a deal on screens, and doesn't charge me art charges. I get more of a break if I supply the shirts myself, which I always do. I just had him screen print a 14 piece order for me and I added numbers on the back and I still made 60.00 profit and spent less than 2 hours on the whole project. I don't make as much as doing it myself, but it frees up time to do the smaller orders and that makes you more money while getting more done.
Being the middle man isn't a bad thing. It's less work. I don't know about you, but pressing 700 shirts with a hot press sounds like way too much work and it would kill my shoulders. Not to mention all of the fumes you'd be taking in. Maybe I'm just lazy

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If the local's don't work out, search this site for lists of contract screenprinters or check the 't-shirt classifieds' on the left hand column. You can post your request and wait for some people to answer. I'd bet there are hundreds of screenprinters out there waiting for a customer like you.