Does anyone make one yet?

You're probably not going to find one because of magazine design.  AR-Fan showed me some pics of one he did.  Drop him a line.

A 17 HMR upper would be so sweet. Maybe DPMS or somone
else will make one of these.

    I built one and it works fine except, as Southern_Raider said, the magazine size. I wanted to use a Grendel 30 round mag but the price was just too much for them. I settled on a Marlin 22 magnum magazine.
    I had read some place that Bushmaster was thinking about building one in either 22 magnum or the 17 HMR but it never seemed to go past the talk stage. Maybe if all the people here that wanted the 22 mag or 17HMR called or wrote to Bushmaster they might just make one -- probably in one of their carbon fiber uppers.