Pete Lockey is a hiker / cyclist who has done many big trips around the world.
He noted my disappointment with the West Highland Way this past Summer, and recommended an alternative:
I was looking for a decent long distance walk in Scotland. The West Highland Way didn’t really appeal, but I found a book describing a route called the Highland High Way which was a high level version of the WHW, and looked a lot more interesting. The book itself described the route as “a magnificent high-level route through some of Scotland’s most dramatic scenery and across some of its finest hills”.
It started in Drymen and finished at Fort William, going in the same direction as the WHW, and sharing many of the overnight stops, but instead of sticking to the valley bottoms it took in high level traverses and summits, including 23 munros. There were 8 one day-stages from start to finish, plus 4 optional ‘day-excursions’ which came back to the same place so could be done without carrying all the camping gear. It all sounded ideal, and I booked a week and a half vacation at the end of May, on the basis that the weather might be OK then, and it would hopefully be too early for the midges. …
read his detailed trip report and see the photos – Highland High Way – May 2009
This looks far more appealing than the “regular” West Highland Way:
* Final munro total: 23 munros (of which I actually saw 13 of them)
* Total Distance: 235 km (146 miles)
* Total Ascent: 18000m (59055 ft)
* Average ascent per day: 1636m (5369 ft)
* Average walking time per day: 9 hrs 40 mins
* Hilliest day: Rowardenan to Ben Vorlich – 2505m (8218 ft)
The 1996 book he used may be hard to find.
The Highland High Way: A High-level Walking Route from Loch Lomond to Fort William by Heather Connon (Author), Paul Roper (Author).
Amazon U.K. claims to have 6 copies available right now.
You get there from 
besthike.com 