Edit: It's official - the 4/23 chapter is the last one for Bakuman.
There's just a hint of desperation in Adachi doing a sequel to Touch, it seems to me, though I'll certainly be fascinated to return to Meisei 26 years later. The new manga will be called "Mix" and will be premièring in Monthly Shounen Sunday next month. I'd just as soon Adachi pick one of his existing series (how many is that?) and update it regularly - especially Over Fence - but you can bet I'll be following this closely.
As for Bakuman, I haven't seen this confirmed by a 100% reliable source yet - thus far only a French site has reported it - but the information appears to be solid. Here's hoping Obata and Ohba don't do Tanto next.