Hacksaw.
I don’t know why I didn’t mention this earlier but besides my giant bags of rice I have for long term storage I also store hard tack(hard bread) Being born and raised in NFLD I ate the stuff quite often as it is part of a lot of traditional fish recipes. I will bet my last dollar that you could store it for 20 years or more with no problem (as long as it is kept dry)
I cannot attest to the nutritional value as such but my great grandfather, and many like him who worked on the sealing vessels ate nothing but hard tack and tea for months on end while doing a days work that would break most of us today. Can’t really argue with history I guess.

As for the rice, you can get the HUGE bags of it here in Edmonton at any superstore location in the Asian food isle for as little as 13 bucks. It’s hard to beat that kind of deal. I also store Mr. Noodles by the case and of course, good old KD. (I think pasta stores forever) I don’t know officially how long rice will last but after reading your post last night I boiled up some from my long terms stores today for lunch and it tasted fine. (It been in my storage for over 8 years)