Hi Al!

I can't tell you about 350 mm long posts, but I can suggest that once you identify the model you want, you watch for it on e-Bay. Usually half or less what a new one costs. Since your bike's post diameter isn't one of the popular sizes (which are 27.2 mm and 31.6 mm), you may have to wait awhile to find what you want. The good news, though, is that the price should be even cheaper!

Happy hunting!