Well, since the original version, for .751, was made in the Unofficial Editor, we had to start from scratch in Python to make an .808 compatible version. So we really haven't been 'porting' anything - we pretty much started over. Some of the weapon models from BaB 0.75 will be featured in version 0.8, but that's about it.
We have about 75 new models to be textured, including period buildings and scene props, period civilian clothing, quite a few new weapons, new merchant items, and several sets of uniforms for both sides (infantry, cavalry, artillery, zouaves, sharpshooters, etc). The new models are going to be a big part of what we've got to do yet, since I'm doing most of the texturing, and I don't have heaps of time to do it
The gameplay mechanics are being completely reworked - by the time we're done, it will be similar to The Last Days, with huge, named armies that spawn from certain locations at certain time periods, whose victories and defeats will affect their faction's strength. Our ideas for this are basically to have the Confederate side start off stronger, whose best chance for victory is to be very quick before the superior manpower and industry of the Union can be Mobilized. If the Union can hold out for about a year (scaled down ingame) then they will start spawning more named armies and larger, too. I'm hoping to use some of the ideas from Pirates mod to incorporate a blockade, complete with naval combat. The quests are all new too and will be much more fun - no running about trying to find 5x of whatever stupid item so and so wanted
There's one where you must steal a train (you actually get to control it from the cab!) another where you must ride through a perilous mountain pass that's heavily guarded to deliver a message, and a lot of quests where you are assigned to reinforce a friendly party fighting a battle or carry ammunition to a stranded unit. When you're knocked unconscious you have a chance of being captured and taken to a prison camp, from which you may have a chance to escape - which would involve killing six sharpshooters with a bowie knife. Smart players would wait for an exchange, I think, because if you die trying to escape the game is over. There will also be a chance of death on the battlefield.
There's going to be several other features like the ability to apprehend or execute deserters, snipe from church towers, and other cool stuff I don't remember or haven't invented yet
As far as actual progress, we're probably 30-40% done with version 0.8 - which I think is acceptable since it's really a whole new mod and shares very little in common with the previous version. We have it playable on .808 but don't plan to release it because the models aren't finished, and neither are most of the new features. As of now, I'd say we will probably have a release for Mount&Blade 0.850 with most of the above mentioned features implemented, by late summer. And definitely by Christmas