Bitcoin was designed from day one to be distributed... your bank account wasn't. I don't think you'll find many people willing to upload their bank account info, credit card or traditional form of payment to a distributed system.
Fiat in Bank Accounts is not meant to be P2P distributed...
Meaning random people sending random SMALL amounts to strangers' accounts...
Based on a some network algorithm they trust.
In fact, doing something like this is probably MORE illegal...
Than just running a Bitcoin exchange...
One could make the case it falls under Racketeering and the RICO statutes.
I'm not aware there is anything illegal about using a bank to make private transactions. In fact, the banks do enjoy the fees.
The law in about INTENT. What it is you are intending to do.
And LE is not stupid. They've seen every kind of smartass.
Forming an organized group where the INTENT is to circumvent Financial Regulations...
Is far more serious than running a public exchange with reasonable compliance like CampBX.