I have always felt one possible solution (not the final solution) for being a fiat or other asset anchor would be to have whatever asset insured by backing it with some locked multi-sig crypto signed by a group of trusted signers that are part of the distribution. I wrote about it here: https://www.funtracker.site/wiki/doku.php#btc_insurance_bonding_fund_in_place_of_fdic_insurance if your interested in details on that.
Also I feel transparency would be required for such methods to work. On our Thailand biz bank accounts we can setup user accounts that can do nothing more then to just view balances. That would have to be accessible to at least a number of auditors and the values should be posted and kept updated to the anchors website at some point so all could view it. I assume most countries must have banks that have such features so this should be possible and done on all fiats in the franchise.
It should be easy for most anyone to check the crypto insurance back deposits. Anyone can view the blockchain info and see how many signatures, signing requirements and balances held in the accounts from the public blockkchain info.
The stellar.org asset distribution accounts are also the same that most anyone can view the signers and how many of each asset has been distributed from public blockchain info in realtime.