Sorry for the long delay I have been away on vacation.
Your response is very valid and indeed in our generated string we do also include product titles, however since changing the order of the aspx attributes our sales have taken off. An issue we have is that we have many products which have very slight variations in name and come up against the the URL too long issue to give real keyword rich titles. We choose to use the attributes to make sure that pages are visited by google on feeds to them, but then generate the title on the fly when the page is rendered. This keeps the url nice and short for Google to locate but allows the spider to see the title in the url. The issue remains that Google are not spidering the all of the attributes but using just the first they come across even if it gives rise to duplicate feeds. You would think that they would index using a sample with all attributes and then with individual attributes to make sure they gain the most content rich and valid results.
We will now run a test to see if truncating the titles improves indexing or shows little or no improvement. I would like to think that this is fairly minor as long as the keywords are close to the start of the title string and hence if Google truncates for result display purposes users will still gain a rich experience.