If you do the math.... the average multiplier for a player is going to be somewhere around 1.9375, which amounts to an average of 97 gold per minute. This can vary between players, but assuming that on average a player does not radically effect the probability of winning or losing, 1.9375x is the average multiplier. This doesn't include the valor bonus.
[You can figure this out by realizing that multiplied over many games, 1x occurs 1/2 of the time, 2x occurs 1/4 of the time, 3x occurs 1/8th of the time, and 4x and 5x both occur 1/16th of the time. Take those multipliers and divide them out, you get 1.9375, or 31/16]
If we do some fuzzy math and assume that every piece of equipment a player owns has the same probability of needing to be repaired, you can figure out the most expensive [in terms of gold] equipment a player could own [theoretically] by multiplying 97 gold per minute by [[100/4]x[100/7]] which is simply the inverse of the percentage likelyhood that at any minute something needs to be repaired, and the percentage of the cost.
That equals 34,643 gold.
Like i said... this is all fuzzy math, and remember that averages can at best only tell us about the outcomes for groups, not individuals.