Bitcoin Forum

Step 1: Create a cryptocurrency of your choice. Have someone else mint it.
Step 2: Create an exchanger, and obtain a Money Service License. You'll now have to verify people that use this exchanger.
Step 3: Buy all the coins that someone else minted for a tiny amount of money. Now start your own miner, but you aren't minting anything at this point.
Step 4: Create a liquidity fund for your cryptocurrency.
Step 5: Artificially set the price at your exchanger to $1 / coin with a small spread.

Result: You have to verify users purchasing currency, but depositors into your liquidity fund don't need to be verified (they're just cryptocurrency users). Your liquidity fund can pay them interest, whatever, tax-free, since it doesn't need to be a money transmitter and doesn't need to know who the users are. Now, whenever somebody wants to withdraw, they have to go back to the exchanger, and withdraw their money, again needing to be verified, only taxing earnings, at any time you wish. Result: Any and all money can be 'IRAified' with no limits.

So you're essentially just creating a fund that always stays at $1 a piece.  Also: I'm pretty sure that there'd be a problem with the interest part of that.