I'm going to have to agree with Planet. And if you don't have a plugin why not program shortcuts into your URL structure?
Specific to the SEO:
1. Google, in their training manual outright stated: sites with too many hyphens are more likely spam. I think they were referring to the domain name... or were they? (doesn't matter because it doesn't take a big leap of the imagination to consider that they don't like hyphens (or long urls) for that matter.
2. Matt Cutts, in various videos/blogs etc. says that the best URL's have LOGIC and can easily be remembered and entered directly into browser.
The list goes on. My advice is to simplify to the easiest/smallest/most logical URL structure you can.