No extensions available. Have a look at Stihl FS46, same as FS45 but has longer shaft, or a straight shaft trimmer.

Should look at Tanaka. Tanaka is the only one I know of that make an extra long trimmer for people 6'3" and over. The shaft is something like 3" longer than any other brand. I was on LS and they have a long thread about this and this is the only one.

At my Echo dealer the other day, I thought I saw an Echo advertized as an extended shaft. Check that out.

We have a Ryobi straight shaft gasoline trimmer (weed wacker.) It was 1/4 the price of a Stihl, on the factory-rebuilt equipment site, and IMO just as good. We had to return the first one and the second was the charm. This is common - and worth it! It's worked well for almost two years.

(I would never have an electric one, they're just too weak.)

Anyway, they have generic attachments available on the market, for straight shaft wackers, and the brands really do seem to be all the same. At least they're compatible. This is the value of a "straight shaft" wacker, even though they're admittedly heavier. They're also more powerful (if you choose carefully.)

We went to Lowe's and got the generic small chainsaw attachment, and it came with a shaft extension that makes the shaft twice as long. It's made to go between the wacker (motor end) and the chainsaw, each of which has its own shaft, so the result is quite long.

(Although Ryobi doesn't recommend it,) I use the extension with the wacker end (as well as with the chainsaw it came with,) quite often, to reach down a VERY steep dropoff at the back of the yard, going down to the road below at a greater angle than 45 degrees. Wacking or mowing anywhere close to the edge is dangerous, it's such a sharp dropoff. I can reach down much farther with the extension, and it may help you. (warning: it's HEAVY)

The little chainsaw (about 8 in. bow) is also very useful for trimming trees. It has a plastic bow, and so is fairly fragile - but if you clean it -each time, use proper notching technique, and don't expect to cut a fat branch, it works OK.

They also make a small plastic snowblower attachment which is the next thing we'll get, and after that, there's a small tiller attachment also available. Yes, they're extremely flimsy and light duty, but if you're careful and maintain them regularly, they work.

And you get that cool extension with the little "pole" chainsaw (tree trimmer.) I would love to find ANOTHER of those extensions to mow even farther down the backyard "cliff."

I feel any major brand pro grade trimmer with a straight shaft vs a bowed shaft will help or solve your problem. I faced the same problem at 5'-11" tall with a bowed shaft with multiple attachments (which are not pro grade IMO). I added a straight shaft to the bowed trimmer with a hard blade attachment only. Purchased an Echo trimmer with straight shaft and use it with string only. My back and trimmers are happy (with faster jobs) when used with my arms fully in the downward position as much as possible.

You will easily get your 3-4" + extra reach with a pro grade trimmer. Plus, you can continue to use your multi purpose power head for what it is better suited for. IMO, multi purpose tools never do all well, compared to a tool doing a job it is designed for. loger

Tanaka's TBC-260PFL is the only long trimmer that I was able to find a few months ago via the internet for my tall relative. It has a shaft 13 or 14 inches longer than others -- 70" versus about 67". Tanaka advertises that it is 14 inches longer and that the cost is about $430.

Not exactly what you are looking for (4 to 6 inches) but here are two extensions of 24" and 36".

Here is a link that might be useful: Outdoor Power Equipment Supplier

you will find the solution at:

www.yard-tamer.com

I know this discussion is 10 years old, and since they do not make the Tanaka anymore, there’s a product that I just bought that will help. I’m 6’3” without shoes, and I have had thoracic spine surgeries. That is that part of the back you bend when you just hunch over enough to trim. Anyway, it got to the point I couldn’t trim, but then after a while, I couldn’t afford the lawn man. I have been looking for some kind of handle for years, and sometime recently (because I check every few months) they came out with “The Darwin’s Grip”. I won’t even try to explain how it looks, but it’s a universal bolt on handle and it is amazing. Either google it, or go here The Darwin’s Grip. The are out of stock right now. When I ordered they were back ordered and it took almost 6 weeks, but at some point they stopped taking orders. I think it’s becoming really popular, and the company hasn’t found a way to scale. Anyway, even if you’re not “tall” it can make the grip more comfortable of just about any trimmer. Check it out.

There are many brands of string trimmers besides Weed Eater. I'm sure you can find a good fit with one of them.