I guess if I had the choice (and sometimes I do), I'd rather grip the big, girthy Glock frame than the narrow magaine.Why can't you grip the magazine itself? I've done that for years with my G26. If the problem is that it looks funny, then why not a +2 extension on a G19 mag? Both would provide extra grip area, both would be cheaper solutions than creating a new frame type (i.e.: the G19X), and neither would create a new pistol that is incompatible with G19s that are already in the .mil supply system.
All of the reloads on my belt are 17 rounders anyway, so I could give a shit about compatibility.