There must be a tool for cutting away rotten wood. Your up on a ladder and you want to remove a section of wood.
A skill saw is too heavy, a jig saw cuts awkwardly. There must be a light small tool
With a cutting wheel for this type of work?

Since the patent has expired on the Fein Multimaster, there are now a lot of substitutes. FEIN Power Tools Inc. - Electric power tools for professionals. has videos on what you can do with the Multimaster.

Here: FEIN Power Tools Inc. - FEIN MULTIMASTER - The universal system for interior work and renovation.

Basically it is an oscillating tool or essentially the same thing that a doctor would use to cut your cast off. The bllade won't cut skin easily, but will cut other things.

Woodcraft and Home Depot have demonstration ares where you can play with the tools carving wood.

The operations are basically sanding, cutting and filing in a unique way.

Even Harbor Freight has gotten into the act. - Harbor Freight Tools - Quality Tools at the Lowest Prices

The Fein version, which I have personally doesn't vibrate as much as the Dremel does. The blades will rotate. Attachments are no interchangeable.

Some of the things that this tool can do with it's cutting baldes is:
1. Cut the bottoms of door jambs
2. Remove moulding
3. Cut a rectangular hole in the middle of a 2 x 4.

Prices of the tool/tool kits range from $40 to $400. The Fein cuttinga blades are about $20 each and the diamond blade is abut $100.



The RotoZip is another tool that comes to mind, but I don't think it's the one you want. http://www.rotozip.com/Shop/ProductDetail.htm?IID=DR01 It's basically a bigger Dremel tool. Or you can think of it as a "not quite a router".

When I read the question I knew who would be me to the punch with his Fein tool. Al good info so far. Cost always catches my eye. The Dremel can be bought at Menards for $99 and Fein goes for about $399 but is more sturdily built. Not had great luck with Harbor Freight but for $39 its pretty much like a Bic disposable lighter for the weekend DIYer