What did I tell you Mike? One look and you'll never want to use plossls again
I'll summarise what I know about a few of the contenders.
For DSO use only I would get the 12nagt4, if you want a double duty ep you can barlow for planetary, the pentax XL is way ahead of the naglers.
12mm Nagler type 4:
One of the best of the entire nagler range. Easy eye placement compared to some other naglers . Didnt perform well with my barlow. Should be able to get for approx $280US + ship on Astromart.
Pentax XL 14mm :
not as wide as a nagler but awesome eye relief and barlows well for me giving less light scatter and sharper image than a shorter nagler type 6 unbarlowed ! Approx $200-220US Astromart.
13mm nagler type 6:
Smaller than both EP's above and with tighter eye relief.
I havent looked through this one personally.
Meade UWA 14mm series 4000
Excellent EP with nagler type field and currently selling for $185US new, a fantastic bargain ! Once stock are sold to make way for the S5000 Meades you will only get them on the 2nd hand market. Downside they are one the biggest and heaviest eyepieces out there.