Ah, no, I agree. I should have been more precise: there should be exclusion of the amounts shown of indefinite goods in any preliminary implementation.If we exclude infinite goods and people want to use it, they'll just put in ridiculously large numbers. If we put them in and people don't want to use it, they won't.
And, regarding your banking system: this is precisely like what I'd like to see. However, there is a significant divergence where a choice need be made: are loans derived from the actual deposits (as in real-life), or are they the creation of fresh money. This choice has large consequences:
If, just as in real-life, loans were the same "physical" money as actual deposits, then banking would also have a great potential to increase money circulation via the "money multiplier" effect. However, with such a system, the total available for loans should be less than its balance; if all of the money was loaned away, the bank couldn't fulfill a request for a given member to withdrawn his or her money, as the bank wouldn't actual have it -- it would be loaned away. The difficulty with this, obviously, is the end of a given set: All members would likely wish to withdraw their money. Unfortunately, this would be quite impossible, as the amount of actual money would be far less than that seemingly held by each country. This system can only work if a certain proportion of countries maintain deposits at any given time (or if there are no loans, which detract from the logic of the whole system).
The alternative, of course, is that the money deposited and the money loaned are completely separate: in basic, if the bank loaned 100% of its holdings, then the money would have essentially doubled; the bank would still retain 100% of the deposits, in addition to creating that amount in loans from thin air. Thus, there is also a virtually (literally and figuratively) unlimited money multiplier, with any given country being able to withdraw its money at any given time, guaranteed. I'm not completely sure of all this system's ramifications, but this would seem the more sensible approach for the present state of the game. If the game was altered so that one didn't need to spend his or her money at the end of the set (i.e., money was more valuable than military, food, energy, etc.), then the prior could work -- which is obviously the more true-to-life scenario.
Regarding Death's comment on the income derived from banks: I quite agree. I think that the value of interest on any savings should be quite low (as in real-life