mastinson,
This is the only breech plug conversion on the market right now that I know of but does not get rid of a carrier, just changes it to a .25 ACP brass case instead of plastic. I don't know of any 209 conversions as of yet.
I am still thinking about getting this conversion for blowback issues only, I don't have any issues with accuracy.
I am sure that with the introduction of the Sidekick, someone will come out with a 209 plug like the Encore/Omega uses and all the Huntsman owners will benefit also.
Here is the .25 ACP conversion.
http://www.prbullet.com/nef.htm