wings,
Yes, you can purchase blind nuts at any hobby shop that carries RC plane stuff.

There's nothing wrong with tapped wing mounting blocks if they're done correctly, and they're not very hard to do. It does involve buying an appropriately sized tap however.

1) Acquire the proper size wing bolts and a tap to match them. (1/4-20 is common)
2) Make sure you have the proper size drill bit for the tap. (When buying a single tap, the drill bit is sometimes included.)
3) You'll also need a tap handle in order to properly tap the hole. (Interchangeable with other taps.)
4) Drill the hole through the wing so that it starts into the wing mounting block.
5) Remove the wing and finish drilling the hole in the block, making sure to keep it perpendicular to the wing holes.
6) Carefully start turning the tap into the hole. It is critical to keep it in line with the hole. Screw it in a few turns, then back it out a few to clear the tap of wood chips. Continue until the hole is tapped all the way through. Take your time!
7) Carefully test the bolts through the wing and into the holes to make sure the holes seem OK.
8) Remove the bolts and place a few drops of thin CA into each wing block hole. Be sure to coat the threads throughout each hole.
9) After you are SURE the CA has fully cured, re-tap the holes with the tap to clear any CA "flash".
Your done!

Keep in mind, you may HAVE to tap a hole someday, so knowing how is a GOOD thing.
Dennis-