Would this work in friction-mode as long as the rear derailleur limit screws are adjusted properly?

Yes

As OFG said, yep, should be more than enough cable pull. Got a pic of the project? We likey piccies!

Yup it works, you can also use Suntour Barcons with Shimano ...been there done that.

Aaron

What barcons have you seen that are 5 speed?

I don't believe that old friction barcons were speed specific, but they did come on 5 speed bikes, I have a Schwinn Sports Tourer on hooks with the optional Schwinn barcons controlling a Campagnolo Gran Sport and 14-34 5 speed Schwinn approved freewheel, the one with the 1" pitch on the two big cogs.

I'd be willing to bet that the Suntour friction barcons have enough cable pull to shift 8, 9, and maybe even 10 speed. Whether or not you'd WANT to shift that thin spacing with friction is another matter.

Duh. I wasn't even thinking...

I've got two bikes that I run 8 speeds in the rear with barcon shifters (pre-indexing) and they work fine. I had to get the rear tensioned just right before I could make it to the lowest cog with consistency.

Is that 130mm spacing on that 8 speed or 126mm? If 130mm there'd be no reason you couldn't shift 10 speed. If 126mm, and you have to be that careful of the tension, there might not be enough pull for 9-10 speed?

Friction shifting on 9-10 speed is AWESOME. I set up SunTour barcons on a 9 and it works flawlessly.

Have you seen 8 cogs in 126mm spacing? I haven't.

BarCons shift over 8sp without a hitch. 6/8 speed is better than 7/9/10, but they'll do it all.

I believe those Schwinn Barcons were in reality Suntour with Schwinn covers on them. And yes they were on 10 speed bikes. I still have a couple sets of the Suntour ones floating around.

Aaron

How about Suntour ratcheting Thumbshifters with a Shimano derailleur and an SRAM cassette? CRAZY world going on out there!!!

Which does bring an indexing question into it... With a 6 or 7 speed setup- Shimano indexed shifters, can you make indexing work on, say a Huret derailleur with a Suntour freewheel? Or is this just a case of "try it, it's so crazy- it just might work"?

No clue, try and see if it works. Most of my bikes use the ORIGINAL indexed shifting

Aaron

Technically, a stock 8-speed cassette would only appear on a 130mm hub, but (as Sheldon Brown taught us) you can put 8 cogs from a 9-speed cassette (or 9 cogs from a 10-speed) on the shorter body of a 126 freehub and so...8 speeds on a 126 hub.
Yes: seen that, done that.

No pics yet; however, I plan on re-gearing my mid-80's Battaglin as a 1x7 setup. Currently setup as a single speed (44x15), it's been my early season late season trainer. Lately, I've been commuting to work on it and taking the long way (25 miles) home. I've been finding myself wanting a little more or a little less gear, so that's where the 1x7 comes in. I plan on keeping the 44 chainring and adding a Suntour 12-18 7-speed free wheel. I have a pair of sweet campy Omega aero wheels with Bullseye hubs that I've been wanting to press into service. The most difficult part right now is finding a barcon at a reasonalbe price. I'll have to use a DT shifter in the mean time, but eventually I would like the avoid takng my hand off the bar to shift.