Instead of creating a headache for yourself, just go for actual cash back cards. BOA's Cash Rewards has a $200 bonus if you go for the MLB version; Chase AARP had a $200 bonus for awhile, etc. That's better than getting tons of miles that you have no use for. Almost all of the true mile programs (i.e. not Venture but actual miles) do not convert to cash at all, or if they do it's a terrible value.