The main purpose of multisig is to prevent someone from accessing your stack if they obtain one key. A 1/2 multisig could be built but would basically have no purpose because there is no security gain when a single signature is all that's needed to move funds.
2/3 or 3/5 are common quorums people often use. 2/2 is possible with only a couple devices, but if you lose any key and its backup then you'd be in trouble.