There's an updated Manta for Wing Commander Collateral Damage now. The color combinations have been made more vibrant and the model has been sharpened up - literally! Menacing spiny points have been added on the edges. JasonRocZ's Secret Ops mod bridges the gap between Secret Ops and Arena, so expect to see quite a few of these out there.
In doing a lot of the Nephilim ships I've been doing textures and not really messing too much with the models themselves... But if I do mess with the models it's only to add a few lil details like updated gun styles, small details here and there.