For any number of millions of dollars donated to Ethereum, what is the total market cap at launch?
And inflation is 26 percent, going exclusively to miners?
Yes, inflation going exclusively to miners.
Say they receive 10000 BTC in their IPO. Assuming the price stays at their imposed value of 2,000 ETH per BTC, the total market cap of current supply at launch will then be:
10000BTC + 10000 BTC *19.8% (dev premine) = 11980 BTC.
If the price somehow remains fixed during the first year, the market cap at year 1 will be 11980*1.26 = 15094 BTC due to inflation.