With a CPU, maybe. How crappy a GPU are you thinking of?
I merged mined with one 5870 and was getting I0Coins fairly often.
Less often lately maybe due to more other people finally bothering to merged-mine, and way the heck less back when it was in bitparking's merged-mining mix, but so what, there has always also been GRouPcoin, CoiLedCoin and GeistGeld, they have always been pretty darn easy and mostly still are even now I think. Though as I recall GRouPcoin actually is higher the last few months than it had been for many months.
If all you have are CPUs, mine Tenebrix and Fairbrix.
Also if you actually care about it, you could add to the bounty offered for tools someone running p2pool with merged mining can use to reward their miners over and above simply providing them a zero fee bitcoin pool.
-MarkM-
EDIT: "difficulty" : 28.78879813 ... That means maybe one needs 28.78+ CPUs to manage to get a block every ten minutes if you are the only one mining? Or what? Maybe 28.77 CPUs should get a block a day? Or every few hours? Or what?