Changing low range ratios?

I haven't seen anything on this topic, so here goes. My '00 Taco has 4.30 diffs behind my 2.7L and 5sp manual tranny. I am currently running 31X10.50 tires and plan to move to 33X12.50s as soon as I wear these out. The thing is this: I like the road performance of my rig, and I think the 33s will be fine, but I wish the low range was a bit lower. I really don't have the need to go the expense of a Marlin Crawler or anything...yet (but here's to hoping). What would it take to change the low range ratio to a lower low range? Does anyone sell a kit or is there a "DIY how-to" somewhere?

 

Jeeps have a *tera-low* kit - but in all honesty? They're just not worth it. I've seen people have more trouble with those types of kits because they (and the rest of the tcase) can't handle the torque.

You're better off getting a crawler, Atlas or Stak transer case. Something that is designed entirely for slow ratios/torque.