I feel your pain. I typically only ride the bike paths in my town in winter as there are fewer people out.
In summer, it's simply too crowded and I switch to auto-jousting.
Though, in your area/route, it may not be practical, pleasant nor safe.
I haven't explored 29ers at all (next MTB), but then I'm still on URT
-- SO TAKE THIS AS AN IDEA TO EXPLORE, NOT A RECOMMENDATION
I don't know if 29er tires will fit a 700c rim, but some MIGHT (I've heard that some of the kendas actually have a 700c spec right on the sidewall, but can't confirm it)
One downside of larger tires is dealing with the caliper brakes (a lot of times with those sorts of wide tire with caliper configurations, you can't put the wheel on with tire inflated) - not the end of the world, but can be a hassle on a commuter
eh, just a thought