IRA vs Roth: rollover or not?

[George Walls]

Given this year's Roth conversion rules, and next year's higher taxes, has anyone done the math to figure out if it makes sense to do a Roth rollover rather than buy in an IRA?

For simplicity assume enough cash on the side to pay the rollover and two options are are: buy a 4 plex in an IRA and a house with after tax cash -- or buy a 4-plex in a Roth and use the after tax cash to pay the taxes on the rollover.