Larry, are you thinking of adding Skylake Celeron to your collection?
I saw some article that said that they were going to be released Q4 '15. Well, they're not here yet. (Apparently, Provantage had them for pre-order, and the 2.9Ghz one was like $57 or so.) I thought about it briefly, and probably would have, if Newegg had them in stock, but I actually just ordered another G4400 to play with. (Since I now have two boards incoming.)
I also started thinking about coolers for them. They come with stock coolers, but unlike the G3258, that was designed for OCing, and included a copper-cored heatsink, the G4400 was only designed to run at stock, so probably only includes an Al heatsink.
Debating on opening one of my BNIB G3258 CPUs, and snagging the heatsink. I really don't want to spend another $30 on a tower heatsink that requires a backplate. (Ok, I know that some of them are cheaper,
with rebate, but rebates are a PITA.)
I have some OCZ Vendetta coolers, but those only came with S775 mounts (and AMD).
Edit: Page 14 of this PDF from HP claims that the SKL Celerons are ETA Q1 '16.
http://h20195.www2.hp.com/v2/GetDocument.aspx?docname=c04790512
These coolers look nice. $45 though. (Dual fans)
New "212 X"
http://www.newegg.com/Product/Product.aspx?Item=13C-000X-00037