After couple muddy rides I decided to make my own sealed cables cheaper than splashing 100 odd pounds on whole system. I still used some parts from Nokon commercial sealed cable system, but the whole project at the end cost 1/5 price.
What I needed:
Nokon teflon liner (1.3mm gears optional 1.7mm for brakes)
Rubber dust covers (aka protection sleeves) for V-brakes
heat shrink 4-2mm
standard Shimano gear cable set and brake cable set (for racer in that example)
nosed ferrules from Shimano 2x for brakes and 4x for gears
also standard set of tools for cable replacement.
cable cutter, Allen keys, angle grinder, pliers, grease, chain oil, silicon grease.
Step 1: Gear Cables
Gear and brake cables been fitted on handlebars as usual. I'm not describing it here. It's fairly standard operation, plenty tutorials can be found on Internet. The only difference I finished the operation with nosed ferrules.
Then I put the liner through bottom bracket guide (pic 5), cut it to size and put heat shrink before feeding inner cables. Then after inner cable installation I've shrink the heat-shrink to form a sealed connection between liner and ferrule nose (pic 2, 3, 4).
I've made sort of sleeve to protect cable coming out underneath front mech. Just a bit of heat-shrink and only front of the pipe been shrink (as you can see on the pic 6, 7, 8, 9). Its kinda hard to show it n the picture but the idea is to protect the liner end from spray and mud. Before installation I've filled the sleeve with silicone grease.
The rear mech was pretty easy to install. I've applied some tension on the cable, cut the liner to exact size and sealed with heat-shrink (pic 10). The remaining exposed piece of the inner cable ideally will be to protect with sleeve like on last picture. Which is rubber sleeve for alfine hub installations, but I couldn't find it separately and looks like is only available as a set with cable and shifter for Shimano Alfine. Instead I used a piece of liner and made similar sleeve as for front mech.
I found the part for the rubber sleeve from Shimano and it's apparently:
SHIMANO spare part Y-6TV98060
SL-S700 OUTER CASING HOLDER UNIT
Shimano Code: Y6TV98060
I might get it at some point, but it's not cheap (£9). Will see...
Step 2: Brake Cables
Brake cables were super easy as the only exposed piece of inner cable was on top tube (pic 4). So, same technique been applied. Both ends nosed ferrules plus a bit of pipe in between. I was quite lucky and I found a piece of pneumatic hose almost exactly same inner dimension as nose of the ferrules. Anyway, Nokon selling same type liner for brakes (http://www.nokon.com/NokonUSA_Products%20%28black%29.htm), and with two pieces of heat-shrink (same as with gear cables) will do the job.
As last thing I've put rubber dust covers from V-brakes on a adjuster threads, and that covers last exposed part of inner cable (pics 5, 6, 7, 8).
Step 3: Some Thoughts
Obviously to fully "winterize" road bicycle, all pivot points needs to be greased (marine grease is quite ok, or chain oil for wet weather). On connections like adjusters, some contact points is good to apply marine grease or silicone grease(water repellent). On my bikes I slowly updated BB bearings to ceramic ones, and the difference is amazing. Not only in terms of friction but they're very hard wearing. Same with jockey wheels, they've been updated to jokey wheels with stainless steel sealed bearings. As always common sense clean bike after ride (less stressful when you've got sealed cables) and lube chain. Decent mudguards (with mudflaps) and we're good to go.