Not sure if anyone has compiled the information into a spreadsheet, but you might check out:

Amtrak is useful for laundering miles and points. Continental and Midwest miles can be transferred 1:1 into Amtrak and Amtrak points can be transferred 1:1 into Continental, Midwest, and United and 1:2 into Hilton. See Does CO->Amtrak->UA really work?

There's the Hilton HHonors Reward Exchange that can turn miles into Hilton points and Hilton points into miles.

Most hotel programs allow you to transfer their points into airline miles, though you can't generally transfer points into those programs except via American Express Membership Rewards and Diners Club.

Diners Club is currently the only way to transfer miles out of United (you can also transfer American miles to Diners points). UA/AA transfer 1:1 into Diners, and then Diners points generally transfer 1:2 into any other airline you want, though the exchange rate varies with some programs and can be better during special promos.

A last resort is always the Points.com exchange, which is usually a very very bad deal. However the current (through June 30, 2004) double conversion bonus with American Airlines helps out, plus there's a 25% bonus now for PointsPlus members. This promo spawned a thread in the American Airlines forum, "Get "UNLIMITED" AA miles for less than $0.01 per mile"

Smarterliving.com has a nice primer on using the various point transfer mechanisms mentioned above. (Though it errs in saying that only American and Midwest remain in the Hilton HHonors Reward Exchange among US carriers (Hawaiian participates as well) and it doesn't draw some of the neat conclusions for you, such as that you can use the Amtrak program as a tool to earn United miles pretty much no matter who you fly amongst US carriers other than America West and Southwest. But it's a pretty good introduction.)

Again, not a spreadsheet, but hope it helps!