The CDI/igniters aren't made by Triumph, but by Gill Instruments. I know what you're going through, but really these are dependable bikes. The igniter box is the only problem I've had with my bike in 3 1/2 years and almost 48,000 miles.
You might want to try and contact Peter Carleo at Triumph here in the USA. Here's his e-mail address:
peter.Carleo@triumphmotorcycles.comHe's helped out on more than one occasion with bikes out of warranty. Worth a shot.
I don't think the problem is so much Triumph itself, but the limited aftermarket that's out there. I knew when I bought my bike that this was the case, and anything aftermarket was going to be slim pickens and probably cost more than your typical Harley of Japanese bike. And those aftermarket companies just don't realize the demand unless we e-mail and call them.
I just checked Bike Bandit, which has OEM parts for about every motorcycle manufacturer and the igniters for comparable bikes run from $350-700 for other brands. So it's not like Triumph is charging a price that's out of line with the rest of the industry. Now that's not to say that Triumph isn't at fault. There's just been too many of these failing when like you said, it's a fairly simple part that shouldn't fail, especially after only 4,000 miles. That's where Procom, or some other company needs to step in and give us a cheaper alternative. We have to let them know though.