The Colorado Republican State Central Committee is composed of party officers from each of the 64 counties, and Republican elected officials, and bonus members. The bonus members for each county are based on how many people voted for the Republican nominee (for the office at the top of the ballot) in the last election. The provision for bonus members says that for each 10,000 votes for the Republican nominee, that county gets another 2 bonus members.
The provision for bonus members is the only mechanism to make membership on the Central Committee roughly proportionate to population. Because Colorado, like almost all states, has many relatively low-population counties and a much smaller number of high-population counties, a committee based entirely on county party officers and elected officials would give a huge majority on the Committee to the small-population counties.
This year, the Republican nominee for Governor only polled 199,034 votes, because most Republican voters voted for the Constitution Party nominee, Tom Tancredo. A normal Republican gubernatorial vote in Colorado is approximately 800,000 votes. As a result of the low vote for the Republican gubernatorial nominee, the Republican State Central Committee, which normally has approximately 400 members, has only 296 members, and they are disproportionately from low-population counties. See this analysis at Craig Steiner’s blog. In retrospect, the party ought to have made the formula dependent on the number of Republican registrants, instead of the gubernatorial vote.