I've been working on 3 Dear Janes in the Block of the Month 2012-2013 Dear Jane Stickle 2d Cyber Party Pictures and Discussion
Today, I went to Ace Hardware to have my custom tri ruler made. My tri's are 8.75" instead of 8". I took the original ruler and one of my printed blocks with the 1/4" seam allowance drawn on it. I also asked him to cut off the tips. It took him about 5 minutes and cost $4. After taking the picture, I decided that lines on the ruler would be nice. I've had a tool in my desk drawer for about 20 years that I've never really used. It's for scratching your name into your expensive metal/plastic electronics in case of theft. It has a very sharp point. A couple lines went crooked and I rescratched, but it turned out great. I did the seam allowances and the center line, which are the ones I've seemed to be using so far.
So if you need a custom ruler, they really are not that expensive!