Found this if it helps anyone - Regarding the converters. On Amazon someone left this information in their review-
The converter needed for the Basic and/or Loom - Faber-Castell Fountain Pen Converter 148785
There are several sellers on Amazon that have them, they appear to run about 5 to 8 dollars with shipping.
Still looking to see if it'll take international long cartridges. Seems as if it should.. but just a guess.