Touring - Schlumpf mountain drive w/rear derailleur?

I was wondering if anyone is using a Schlumpf mountain drive with a rear derailleur on their touring bike?

I've heard some people describe a "drag" or "compression", a whine, and/or a wobble when it's engaged, but they might also be using an internal hub, and maybe that's where the problem lies? I don't really know about internal hubs.

Also, do you think it's reliable and can withstand 10,000 loaded touring miles with little chance of breaking or wearing to the point where a bike mechanic would be required? I'd consider my current XT setup as meeting these requirements, if there are only a few slow-speed crashes and proper lubrication and cleaning are done while on tour.

Thanks!

The cost and loss of efficiency of a Schlumpf makes me question what's the point in replacing a front derailleur with a friction shifter? Front shifts are easy with that setup and almost foolproof - not much to go wrong and easily repaired replaced should there be an issue.

I'm interested in the Schlumpf because you can achieve extremely low gearing with it, below 15in if you want. Setting aside my reasoning for wanting the Schlumpf, I was wondering if you know about any "dragging" or noise or wobbling when its engaged. Some report that there is some, others don't mention it at all.

I have heard of issues related to the efficiency of the transmission when the over/under drive [depending on model] is engaged. These BB systems are used more commonly on recumbents. I'd post your questions over at Bent Rider Online (http://www.bentrideronline.com/). They'll be some owners who can give you some detailed feedback.