edit 11/25/17 if you are interested in BuildTak's FlexPlate system, take a look at my additional mod I've posted here: https://www.thingiverse.com/thing:2669280
I'm very pleased with how this mod turned out. It is quite simple and can completely be reverted if you so choose. I really can't believe I didn't think to do this sooner, but I'm trying to buy as much life out of my Taz 4 as possible and the only area I haven't upgraded is the bed leveling.
The dial is a remix of the model I've linked to and both the bottom and top (aka 'fingers') models are remixes of the originals. The bed 'fingers' are longer to better hold the glass in place, but do not interfere with the home position (it's a bit close, but it doesn't touch the hotend). The bottom has been remixed to better slide up and down inverted bolts.
(8) 20mm m3 bolts (https://www.mcmaster.com/mv1509661997/#catalog/91290A123)
(4) 25mm m3 bolts (https://www.mcmaster.com/mv1509661997/#catalog/91290A125)
(4) m3 heat inserts (https://www.mcmaster.com/mv1509661997/#catalog/94180A331)
(8) springs (https://www.homedepot.com/p/Everbilt-Spring-Assortment-Kit-84-Pack-13554/203133714)
I am honestly unsure which springs I used, as I didn't have any and bought two variety packs from Home Depot. They are slightly shorter than the existing springs used to level the bed. They are also not as strong as the existing springs, but fairly stiff. It requires two variety packs, but you get a lot more springs for the price of a small bag from McMaster.
Step 1 - print (4) of each of the three models
Step 2 - insert the heat inserts into each of the dials
Step 3 - heat press the 25mm bolts into the Bed Leveler 'fingers'
- trick - I used a heat insert to make the hole, removed it, then inserted the bolt with heat
Step 4 - disassemble the bed and remove it and the stock corner parts
Step 5 - Use a drill to slightly expand the unused, pre-drilled hole in each corner enough to allow the m3 bolt to freely pass through it
Step 6 - Screw the (8) 20mm bolts in from the bottom (two in each corner) of the originally used holes so that the threads face up
Step 7 - place the new springs over each of the inverted screws
Step 8 - place the bottom bed leveler part of the bed leveler onto each corner
Step 9 - place the glass bed back into position
Step 10 - place the original springs in between the bottom bed leveler part and the corner holes
Step 11 - put the bed leveler 'finger' in the corner hole of the bottom bed leveler part, from the top, through the original spring, and the previously drilled expanded hole in each corner
Step 12 - compress the bed leveler 'finger' and screw the dial in from below
Step 13 - relevel the bed