If your really worried about anyone having your bank information, you better stop writing personal checks. Your routing and account number are printed right on your check.
When you do a wire transfer, your bank is getting funds directly from the buyers bank, and its all 100% Federally controlled. The funds are the same as cash. No checks, no 21 days to clear the FED. Right now CASH. In your hand.
And if your afraid of electronics, you better give up all together. There is no paper transaction with banks anymore, other than storage, and I think even that has ended. All checks are scanned electronically and stored electronically, all transactions are fully electronic between banks and the Fed Res. The only reason the Fed waits 21 days is simply a safety net for all involved
Also, unlike just a few years ago, identity theft has forced banks to guarantee your funds better. I dont know if its all banks, or a Federal law, but every bank I have dealt with the last 5 or 6 years guaranteed my funds after the first $50.
The one to really watch out for is Paypal. You give paypal the right to access your account when you sign up. If your buyer/seller complains to paypal, they can reach into your account and take any amount they see fit. And because you authorized them to have access to your account, your Bank cant stop them. They are also offshore, so the Fed cant do anything either. They took over $1000 out of my account as a "hold", because they thought I was selling to much stuff and decided I was a risk. The only problem is that unlike all the other transaction where they email you, they dont do that when they take it from you. I will eat dirt before I ever deal with them again.
Postal Money Orders are "okay", but if lost will take 90 days to be replaced. I wouldnt accept one from anywhere else, and wouldn't cash it anywhere else. Western Union is "okay", but its expensive and its a hassle and I believe there is a $3000 limit.
I have had bank wire transfers over $10,000 and never had a problem. I too was worried about giving out my routing and account number, until the bank person reminded me its on my checks. Well duh!
Stop being afraid and just do it the right way. Have them wire the money to your bank and they can take the boat ASAP. Done. And no, they cannot undo it for any reason because it is a cash transaction.