Just in case you might be interested, the old Dark forces mod levels (you know, the pack of three maps) worked in ojp's co-op. I played through after adding appropriate arena files and removing other effects (laser bolts and such that caused crashing). I don't know about the new pack of six, but you could possibly implement those maps for use in ojp (once more, if you are interested).
I just thought that Dark Forces was really fun, saw this topic, and thought it was a believeable approach. After all, six maps are practically done for you.
Keep life interesting: always question the naturally accepted.