Putting money that is really yours in someone else’s name in order to skirt federal regulations seems like a clear cut case of fraud to me.
The chances of you getting caught are slim, but there are other, non fraud ways to buy extra i bonds. Like mentioned above, you and your spouse can gift each other as much as you want, and they will start accruing interest right away, even though you can only redeem 10k purchase price per year.
You can also set up as many trusts as you want, and each trust can buy 10k.