1. Ebay it as a broken iPhone. I've seen them get over $200... mention the comm board is bad, and that there's no water damage. I bet you'll get over $250 for it.
2. Take it apart to the point where you can show where the hack went wrong and take it to a local electronics repair place and see what they think. Professional electronic repair guys are often really impressively good. (but also sometimes they aren't... it's very hit or miss). A good professional electronics repair guy should be very good at scraping off solder mask and then doing a precision high-quality solder to a sub-mm trace. Check the phone book for TV repair or electronics repair. Call around to the guys in the book and describe the problem in general terms... I don't think I'd say "hey, I have a broken iPhone that needs fixing"... that'll just freak them out. You didn't say what is wrong exactly, but I presume you cut the A17 trace when trying to strip down the solder mask to make a solder point, so just say "I cut a 1mm trace on a PCB board and I need to have a wire jumper soldered onto it". This option is likely to be the most time-consuming, but also the cheapest. The repair should run you less than $75 - probably $30-$50 if the problem is just a cut A17 trace.
3. Google "iphone repair" and then choose one of the numerous places on there, research them a bit to make sure they are legit, and send your iPhone to them. Tell them the comm board is bad and ask them to swap it. Should run less than $100.
4. Take it to an Apple store - or call them - and tell them that you broke it and be as vague on the details as you can be. Lie if your ethics allow it, but if not, say that you physically damaged it doing something. In any case, tell them it's not water-damaged but that it's not a covered warranty repair. Just ask them to fix it. This is likely to be an awkward conversation and may run you up to around $150, but I don't know anyone who has done this so I don't know.
5. Buy a broken iPhone on Ebay - make sure it's not water damaged. Swap comm boards. This is probably the riskiest idea and is likely to be the most expensive. Broken iPhones are going for >$200... and I would bet that some of them are water damaged...