It looks like Poland is developing their own version of the XM29 OICW concept, according to the MSPO 2008 website. It may or may not be called the “Neon”, Google translate is not great at best of times.
What makes the Polish concept unique is that the grenade launcher part of the weapon will, at this stage in the design, be able to be removed and swapped for a different caliber, either 40mm or 25mm.
I am going to predict that they will end up with one caliber and not bother with the complexity and cost of multiple calibers.
It has the usual fire control system to program air burst grenades to detonate at a certain distance.
I will be watching with interest to see what happens with this program. Sweden and Singapore are also developing similar weapons and South Korea will be fielding the XK11 Korean New Rifle in 2010.
More information here (translated with google)
I have done my best to find accurate information about this firearm on the Polish MSPO 2008 website. I do not speak or read Polish so I had to rely on Google Translate. If I got something wrong, please correct me in the comments.