Do any mountaineering / Alpine style waterproof trousers come in short legs? I have a 29" inside leg and I've really struggled to find anything to fit.
Look in the women's section of your favorite clothing supplier.
The average woman is shorter than the average man, which means there are often smaller sizes in these selections. They also have some options that are not available in mens clothes.
Unfortunately Women's clothes often have small pockets, so when shopping the women's section, besure to test the pockets before purchasing.
Not ashamed to say, some of my outdoor clothes come from the women's section.
This assumes they are normal pants, without a zipper on the leg.
Put them on, then roll up the cuffs to the length you want. Normally pants that are worn with boots are 1-2" longer to keep the bottom over your boot top even with a sharply bent knee.
Safety pin them in place.
Go to your local dry-cleaner and ask if they do alterations. Usually changing the length of pants is just a few dollars.