Is it possible to do a 3-of-5 OR 1 multi-sig for backup purposes? I'd like to create a multi-sig wallet where I can freely create transactions, but I want to give keys to trusted friends/family + a safety deposit box so that if I hit my head and forget my password, or I die, then the trusted people can recover my coins.

Is this something Bitcoin currently supports or plans to support?
Yes, this is possible. You can construct a script such as:

OP_IF
    &lt;key1&gt;
    OP_CHECKSIG
OP_ELSE
    OP_3
    &lt;key2&gt;
    &lt;key3&gt;
    &lt;key4&gt;
    &lt;key5&gt;
    &lt;key6&gt;
    OP_5
    OP_CHECKMULTISIG
OP_ENDIF


This will allow key1 to freely spend the coins, but if a signature from key1 is not present it also allows any 3 of the keys2-6 to spend the coins.