I don't know of anyone in particular.  That does sound high but...  Do you know if this guy actually has experience working with ARs?  Just because he's a smith doesn't mean he knows an AR from his ass.  I've seen the results of 'smiths' work on ARs for the first time.  

If this guy has experience with this kind of work, AND HAS THE RIGHT TOOLS (no, I'm not kidding), then you may just have to break down and pay him.  Otherwise, you can probably locate someone else, even if you ship the upper out, but you will likely approach $70 with shipping.

Perhaps Lion_Dog will sniff his way by here, I think he knows of a good smith or two up thar in the north.

The other option is to buy the tools, a video, and do it yourself.  You will certainly spend the $70 on tools but, you will have them forever and be that much more proficient at maintaining your own firearm.  An armorer's video (shows you how to build an AR from the ground up), barrel wrench and receiver vice blocks can be had from Bushmaster, among others.  A strap wrench and vice can be had from Home Depot.  I know folks who've learned and later kicked themselves for not learning earlier.  Its not really that hard at all...

Good luck!

Have you considered shipping it out? I think "BrightFlashlights" could install it and I'd bet Adco certainly could, might still be less than $ 70 with shipping back and forth.

Do you need a special wrench to install those YHM handguards/

Aimless, Chapper thanks for the reccomendation.  Forearm installation is something we'll do on a limited basis (when time allows.)  We can do so until mid-November but then we pretty much have to stop accepting build projects due to the oncoming Christmas rush.  The price is $40 for the disassembly & reassembly and turn around time is 3-5 business days (from the time it arrives here).  Any incoming upper MUST be insured and return shipping will of course be insured!