According to Blic, it is DS + the Hungarian Coalition + SPS. Blic is close to DS and may have inside information, and they promise more detail in tomorrow's edition (NB: Blic does not always make good on promises of this type). The article claims the deal will be announced when the final results are announced, which should be Thursday night at the latest.
Do I have an opinion on this possibility? I do indeed have several. They vary between two extremes -- the first of which is that it would be a shame to see criminals back in power again (moderating factor: they never left), and the second is that if SPS were ever to become a real political party with a programme that bears some resemblance to its name, this would be good for everyone.
Update: Tihomir Loza has some reflections on the subject too.