He pushed for Romneycare in Massachusetts, so probably on the healthcare.
Different constituencies means different political pressures. There's no way Romney would push for anything remotely resembling Romneycare.
Raise income taxes? Sure, Romney might do it in exchange for another pound of flesh- say, another couple trillion dollars injected into the economy that first goes through the banks.
His official tax plan says otherwise. You can accuse him of lying, but then that falls squarely into the "conspiracy theory" category.
It's not like Obama has made a serious attempt to raise taxes either- it's mostly just a talking point to appear like he supports the 99%.
Again, look at the tax policy for his potential second term. Big hikes in a lot of places, high-income earners and businesses especially.
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The Many Forms of Kobe:
http://i39.tinypic.com/oqx98z.jpg -- credit to KIRBEH