I have your current gear set up to the tee and have my stock 1.3 f.i and feel the crawl ratio of 129:1 is the shiznit. I which I had more motor like your 1.6 setup though, to be able to use the higher gears with confidence. I cant see that you would need more gearing with your current combo. If you add a second t-case it would be at 232:1, insane. Of course depending on what tire size you are running, it may be your cup of tea.
Stock sammy axles with 5.38's, max tire size of 33. Dana 44 with 5.38's, max tire size of 38's. What axle setup and tire combo you have. Sounds like you have a possible non street legal rig. I wheel with a couple of guys that use the OTT stuff, Mudmonger and SHE996 on the pirate board. Do a search on Pirate for their know how.